1. Chemical Vapor Deposition （化学气相沉积）
CVD
合同期满述职报告
the first group
Chemical Vapor Deposition （化学气相沉积）
Group One
汪小知
浙江大学信息与电子工程系

2. Outline Introduction CVD Reaction Process CVD Equipment
the first group
Outline
Introduction
CVD Reaction Process
CVD Equipment
Various Chemical Vapour Deposition

3. Introduction single-crystal diamond grown by CVD
the first group
Introduction
Author: 祝晓琪
Presenter: 张怡颖
single-crystal diamond grown by CVD
The gem- sized single crystals of diamond grown by special microwave plasma chemical-vapour deposition （ MPCVD：微波等离子体化学气相沉积）technique that produces crystals at very high growth rates(2.5mm high, grown in 1day), up to 100 times faster than is usual.
2.5mm high,grown in 1day
CS Yan et al Physica Status Solidi (a) 201 R25.

4. Introduction What is CVD? gas decomposition gas reaction
the first group
Introduction
Author: 祝晓琪
Presenter: 张怡颖
What is CVD?
Chemical vapor deposition (CVD) is a chemical process used to produce high-purity, high-performance solid materials. The process is often used in the semiconductor industry to produce thin films(薄膜). In a typical CVD process, the wafer (substrate) is exposed to one or more volatile precursors, which react and/or decompose (分解)on the substrate surface to produce the desired deposit. Frequently, volatile by-products are also produced, which are removed by gas flow through the reaction chamber(反应室).
2.5mm high,grown in 1day
gas inlet(进气口)
gas decomposition
gas reaction
gas exhaust(排出)
substrate adsorption

5. Introduction types of CVD classify by pressure
the first group
Introduction
Author: 祝晓琪
Presenter: 张怡颖
types of CVD
classify by pressure
Low Pressure CVD (LPCVD)
Very Low Pressure CVD (VLPCVD)
Atmospheric Pressure CVD (APCVD)
Ultra High Vacuum CVD (UHVCVD)
Plasma Enhanced CVD (PECVD) (等离子体增强化学气相沉积)
Laser Enhanced CVD (LECVD) (激光表面增强化学气相沉积)
Metal Organic CVD (MOCVD) (有机金属化学气相沉积)
Electron Cyclotron Resonance CVD (ECRCVD) (电子回旋共振化学气相沉积) …
2.5mm high,grown in 1day

6. Polycrystalline Silicon Silicon dioxide（二氧化硅）
CVD
the first group
Introduction
Author: 祝晓琪
Presenter: 张怡颖
Applications of CVD
Customized Surfaces
Epitaxial Layers (外延层)
Conductors(电导体)
Polycrystalline Silicon
Barriers
Silicon Nitride（氮化硅）
Insulator（绝缘体）
Silicon dioxide（二氧化硅）
2.5mm high,grown in 1day

7. Introduction Applications of CVD: MOS fabrication
the first group
Introduction
Author: 祝晓琪
Presenter: 张怡颖
Applications of CVD: MOS fabrication
Application: gate of MOSFET, surface micromachining
Usually deposited in a LPCVD chamber
In situ doping can be performed– usually perform thermal diffusion right after polysilicon(多晶硅) deposition
2.5mm high,grown in 1day
at Pa, C, Ǻ/min

8. CVD Reaction Process Types of CVD reactions Thermal decomposition 热分解
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Types of CVD reactions
Thermal decomposition 热分解
AB(g) ---> A(s) + B(g)
ex: Si deposition from Silane at 650 C
SiH4(g) ---> Si(s) + 2H2(g)
Ni(CO)4(g) ---> Si(s) + 2H2(g) (180oC)
use to deposit: Al, Ti, Pb, Mo, Fe, Ni, B, Zr, C, Si, Ge, SiO2, Al2O3, MnO2, BN, Si3N4, GaN, Si1-xGex, . . .
2.5mm high,grown in 1day

9. CVD Reaction Process Types of CVD reactions Reduction 还原
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Types of CVD reactions
Reduction 还原
AX(g) + H2(g) <===> A(s) + HX(g)
often using H2 (metal, substrate)
- often lower temperature than pyrolysis
- reversible => can use for cleaning too
ex: WF6(g) ) + 3H2(g) ---> W(s) + 6HF(g) (300oC)
MoF6(g) ) + 3H2(g) ---> Mo(s) + 6HF(g) (300oC)
- use to deposit: Al, Ti, Sn, Ta, Nb, Cr, Mo, Fe, B, Si, Ge, TaB, TiB2, SiO2, BP, Nb3Ge, Si1-xGex, . .
2.5mm high,grown in 1day

10. CVD Reaction Process Types of CVD reactions Oxidation/Nitrition 氧化/氮化
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Types of CVD reactions
Oxidation/Nitrition 氧化/氮化
AX(g) + O2(g) ---> AO(s) + [O]X(g)
often using O2 /N2
ex: SiH4(g) + O2(g) ---> SiO2(s) + 2H2(g)
SiO2 deposition from silane and oxygen at 450oC
lower temp than thermal oxidation
use to deposit: Al2O3, TiO2, Ta2O5, SnO2, ZnO, . . .
2.5mm high,grown in 1day

11. CVD Reaction Process Types of CVD reactions Exchange 置换
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Types of CVD reactions
Exchange 置换
AX(g) + NH3(g) ---> AN(s) + HX(g)
often using amonia or water vapor
AX(g) + H2O(g) ---> AO(s) + HX(g)
ex: BF3(g) + NH3(g) ---> BN(s) + 3HF(g)
deposit wear resistant film (BN) at 1100oC
use to deposit: TiN, TaN, AlN, SiC, Al2O3, In2O3, SnO2, SiO2, . . .
2.5mm high,grown in 1day

12. CVD Reaction Process Types of CVD reactions Disproportionation 歧化
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Types of CVD reactions
Disproportionation 歧化
2AB(g) <===> A(s) + AB2(g)
compounds involving elements with multiple valence states 价态
ex:                                                            
use to deposit: Al, C, Ge, Si, III-V compounds
2.5mm high,grown in 1day

13. CVD Reaction Process Types of CVD reactions Reversible Transfer 传递 ex:
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Types of CVD reactions
Reversible Transfer 传递
ex:                                                       
use to deposit: GaInAs, AlGaAs, InP, FeSi2, . . .
2.5mm high,grown in 1day

14. CVD Reaction Process CVD Film Growth Steps
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
CVD Film Growth Steps
1.Reactant gases enter the reactor.
2.Gases diffuse through the boundary layer.
3. Gases come in contact with surface of substrate.
4.Deposition reaction takes place on surface of substrat.
5.Gaseous by-products of the reaction are diffused out of the surface.
2.5mm high,grown in 1day

15. CVD Reaction Process Author: 陈耀玲 Presenter: 秦 贺 CVD the first group
2.5mm high,grown in 1day

16. CVD Reaction Process CVD Sources types of sources gases (easiest)
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
CVD Sources
types of sources
gases (easiest)
volatile liquids （挥发性液体）
sublimable solids （可升华固体）
combination
2.5mm high,grown in 1day
source
gases
reactor

17. CVD Reaction Process Gases
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Gases
The reactants (including diluent （稀释液）, extender, and carrier gases) must be transported and metered in a controlled manner into the reactor.
In the case of gaseous reactants, this does not present any particular problem and is accomplished by means of pressure controllers, gauges（计量表）, flowmeters（流量计）, and mass-flow controllers（流量控制器）.
2.5mm high,grown in 1day

18. CVD Reaction Process volatile liquids
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
volatile liquids
Many of the CVD reactants are liquid at room temperature.They must be heated to their evaporation（蒸发） temperature and transported into the reaction chamber （反应箱）by a carrier gas, which may be an inert gas（惰性气体） such as argon（氩气） , or another reactant such as hydrogen（氢气）.
2.5mm high,grown in 1day

19. CVD Reaction Process sublimable solids
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
sublimable solids
Reactants which are solid at room temperature present more of a problem since they must be heated to their vaporization temperature（蒸发温度）, which in some cases may be relatively high.
2.5mm high,grown in 1day

20. CVD Reaction Process Source materials should be
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Source materials should be
1.stable at room temperature 稳定
2.sufficiently volatile 挥发性
high enough partial pressure to get good growth rates
3.reaction temperature < melting point of substrate
4.produce desired element on substrate with easily removable by-products
5.low toxicity 低毒性
2.5mm high,grown in 1day

21. CVD Reaction Process Substrates
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Substrates
need to consider --besides its properties
adsorption （吸附）
surface reactions （表面反应）
ex: WF6 +SiO2 ➝WOF4 ↓+SiOF2 
WF6 deposits on Si but not on SiO2
2.5mm high,grown in 1day

22. CVD Reaction Process Growth of films depends on
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Growth of films
depends on
transport of gas to surface
adsorption of gas on substrate
reaction rates on substrate
transport of products away from substrate
2.5mm high,grown in 1day

23. CVD Reaction Process Mass transport in gas goals ：
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Mass transport in gas
goals ：
1.deliver gas uniformly to substrate (uniform films)
2.optimize flow for maximum deposition rate
2.5mm high,grown in 1day

24. CVD Reaction Process Two flow regimes（两相流机制） Molecular flow 分子流动
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Two flow regimes（两相流机制）
Molecular flow 分子流动
diffusion in gas
D ~ T3/2 / P from Kinetic Theory of Gasses
reduce Pressure for higher D (diffusion coefficient)（扩散系数）and higher deposition rate
2.5mm high,grown in 1day
Viscous flow 粘滞流动
low flow rates produces laminar flow (desired)
（低流量：层流，有利沉积）
high flow rates produces turbulent flow (avoid)
（高流量：湍流，尽量避免）

25. CVD Reaction Process laminar flow层流: simple case-- flow past a plate
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
laminar flow层流: simple case-- flow past a plate
                                               
near plate velocity = 0 ==> stagnant layer
（近板层） (滞流层、边界层)
diffuse gas through stagnant layer to surface
2.5mm high,grown in 1day

26. CVD Reaction Process mass transport depends on fundamental parameters
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
mass transport depends on
fundamental parameters
experimental parameters
reactant concentration
（反应物浓度）
pressure(压力）
diffusivity（扩散率）
gas velocity（气体速率）
boundary layer thickness
（边界层厚度）
temperature distribution
reactor geometry
gas properties (viscosity (粘性). . .)
2.5mm high,grown in 1day

27. CVD Reaction Process vapor diffusion model（气相扩散模型）
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
vapor diffusion model（气相扩散模型）
AB(g) ---> A(s) + B(g)
                               
F1 = flux to surface（到达表面的流量）
F2 = flux consumed in film（薄膜形成的消耗流量）
CG = concentration of AB in gas（气体中的AB浓度）
CS = concentration of AB at surface（基体表面的AB浓度）
2.5mm high,grown in 1day

28. CVD Reaction Process vapor diffusion model（气相扩散模型）
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
vapor diffusion model（气相扩散模型）
F1 = hG (CG - CS)=D/δ*(nG-nS)
where hG = gas diffusion rate constant, or D
D∝T3/2/P (P是压力）
F2 = kS CS
where ks = surface rate constant （表面速率常数）
in steady state: F1 = F2 = F （稳态）
growth rate of film is proportional to F
2.5mm high,grown in 1day

29. CVD Reaction Process Two rate-limiting cases（两种速率决定机制）
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
Two rate-limiting cases（两种速率决定机制）
a mass transfer limited 传质决定机制
small hG
growth controlled by transfer to substrate
（到达基板的传质决定生长速率）
hG is not very temperature dependent
common limit at higher temperatures
（通常是高温下的决定机制）
lower pressure, higher T → higher D
→ Quicker diffusion
2.5mm high,grown in 1day

30. CVD Reaction Process pressure and temperature are high.
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
pressure and temperature are high.
the gas velocity is low
the boundary layer is thicker
the temperature is higher
the decomposition
reaction occurs more
rapidly and any molecule
that reaches the surface
reacts instantly.
2.5mm high,grown in 1day

31. CVD Reaction Process surface reaction limited （表面反应决定）
the first group
CVD Reaction Process
Author: 陈耀玲
Presenter: 秦 贺
surface reaction limited （表面反应决定）
kS =C*exp(-Er/RT) --surface rate constant
small kS
growth controlled by processes on surface
adsorption（吸附）
decomposition （分解）
surface migration（表面迁移）
chemical reaction
desorption of products（产物脱落）
kS =C*exp(-Er/RT) is highly temperature dependent (increases with T)
common limit at lower temperatures
（通常是低温下的决定机制）
2.5mm high,grown in 1day

32. The gas phase reaction chamber（ 化学气相反应室）
The core of the gas phase of the reaction chamber is to obtain a film as uniform as possible.
Since the CVD reaction on the surface of the substrate was carried out, it is necessary to consider how to control the gas phase reaction, the substrate surface can be fully and timely supply of oxygen.
In addition, the reaction products must also be able to put it removed.
Gas phase reactor has horizontal, vertical, cylindrical several.

33. The structure of the reaction chamber
1.Open system
The equipment continues to supply the gas reaction and removes the  by-products
The pressure of the equipment keeps constant, the pressure is slightly higher than one atmospheric pressure.
The pressure is benefit for discharging waste gas.

34. The structure of the reaction chamber
horizontal structure（水平/卧式）
Characteristics：
High productivity
The concentration of the gas and the thickness of the film are not uniform alone the direction of the gas flowing.

35. The structure of the reaction chamber
vertical structure（垂直/立式）
Characteristics：
Low productivity
The thickness of the film is uniform.

36. The structure of the reaction chamber
cylindrical structure（圆筒式）
Characteristics：
High productivity
The thickness of the film is uniform.

37. Heating methods 1.the resistance heating（电阻）
2.the induction heating（电磁感应）
3.Infrared radiation heating（红外）
4.Laser heating（激光）

38. Heating methods
Common methods: resistance heating and induction heating.
Induction heating: only be used to heat graphite.
Infrared radiation heating: focused heat can be further enhanced thermal effects, the substrate is heated rapidly localized heating.
Laser heating: keep the temperature of the substrate increasing rapidly slight localized by moving the beam spot to scan continuous heating.

39. Hot wall CVD & Cold wall CVD
Range of application:
When the reactants are volatile gas, the wall of the reaction chamber should be heated.
The reaction material can be gas, liquid and solid. The liquid and solid should be heated.
The materials that will react in the low temperature should be isolated.

40. Ⅲ. Hot wall CVD & Cold wall CVD
Cold wall CVD: Hot wall CVD:

41. The closed system The reaction carry out in a closed pipe.
Make the pipe vacuum. Put the materials into the pipe, then close the pipe.
The difference of the temperature in the each side of the pipe make the chemical transport reactions carry out.

42. Ⅳ. The closed system
Reaction equipment:

43. Ⅳ. The closed system Advantages: Less pollution
There is no need to continuous to suction for keep the reaction chamber vacuum.
Disadvantages:
Low productivity
Not suitable for mass production

44. Gas control system（气体控制系统）
CVD reaction system using a variety of gases, such as raw material gas, oxidizing agents, reducing agents, carrier gas, etc., to prepare thin films of high quality, the ratio of the gases should be precisely controlled.
Currently monitoring components used primarily by the flow meter （质量流量计）and needle valve（针形阀） quality.

45. Exhaust treatment system（尾气处理）
CVD reaction gases are mostly toxic（毒性） or strong corrosive（强氧化性）, and therefore need to be treated before discharge. Usually cold absorption or by washing the waterfront, after neutralization and disposal and treatment response.
With the deterioration of the global environment and the requirements of environmental protection, advanced exhaust aftertreatment system in CVD equipment has become a very important part.

46. In addition
In addition to the component described above, according to the different types and different responses to sediment deposition reaction chamber design of the internal structure, and in some devices the energy needed to increase the excitation control means, or if other energy plasma enhanced activated apparatus（能源激励装置）, there exists such a device. The following detailed description of some of the reactions producing device.

47. Pressure single-crystal epitaxial and polycrystalline thin film deposition apparatus（常压单晶外延和多晶薄膜装置）
Figure 1 are some of the atmospheric epitaxial single crystal and polycrystalline thin film deposition apparatus schematic.
Figure 1 (a) is the simplest horizontal reactor; Figure 1 (b) is a vertical reactor; Figure 1 (c) is a barrel reactor.
Three device not only can be used for the epitaxial growth of silicon, are more widely used in other epitaxial layer GaAs, AsPAs, GeSi alloy and SiC and other growth; also used silicon oxide, silicon nitride; fund is deposited polysilicon films, etc..
Figure 1 Change the apparatus can be seen to gradually increase the yield of each operation, (a) means the substrate 3 to 4, (b) the discharge device can be 6 to 18 / times. (c) means 24 to 30 can be placed / times. However, such changes can not be far from meeting the needs of the rapid development of integrated circuits.

48. Figure 1(a)：horizontal reactor

49. Figure 1(b)：a vertical reactor

50. Figure 1(c)：the barrel reactor

51. the Productivity is rising
3 ~ 4
2018/9/17
6 ~ 18
24 ~ 30

52. Hot wall LPCVD device（热壁低压CVD）
Hot wall LPCVD device appears as shown in Figure 2 and the corresponding process, a major breakthrough in the late 1970s known as the integrated circuit manufacturing process.
LPCVD reactor itself is composed of quartz after annealing surround the periphery of the quartz tube is a tube used to carry out the heating device, since divided into three parts, called "three-zone heater"（三区加热）.
Gas furnace tube is usually from the front, and not far from the door, into the inner tube (of course, there are other different design methods). The substrate to be deposited, is placed on the same is made to match the wafer boat and the wafer boat with, the tube into position for deposition. The rest of the deposition reaction gas, the vacuum system via CVD was discharged from the device.

53. Figure 2 ：Schematic diagram of the hot wall LPCVD

54. Figure 2 shows the LPCVD using upright inserts increased silicon capacity. Since the deposited film is usually only required on one side wafer, so each cell can be placed back to back two wafers.
If each grid spacing of 5mm, then 600mm long reaction zone can be placed 200. Deposited under low pressure the mean free path of gas molecules is much larger than the atmospheric pressure, the corresponding rate of molecular diffusion is much larger.
Due to greatly accelerate the process of transporting the gas molecules, although the vertical airflow direction and silicon gas molecules able to react quickly spread to the surface of the wafer children get uniform deposition layer.

55. In modern LSI technology inside
In modern LSI technology inside. In hot-wall LPCVD deposition material, mainly the polysilicon, silicon dioxide and silicon nitride.
The process control temperature of about 400 ~ 850 ℃. Several Torr in pressure between 0.1Torr.
Such as the CVD reaction chamber are at the reaction temperature, etc. Therefore, the wall will have to deposition, the tube must be cleaned periodically.

56. Plasma enhanced CVD apparatus 等离子体增强CVD
Plasma-enhanced CVD apparatus of the deposited by plasma enhanced CVD techniques to decrease the temperature of several hundred degrees, and sometimes even get CVD film on the substrate at room temperature. Figure 3 shows several (PECVD) apparatus.

57. Figure3(a):the simplest means of PECVD inductively coupled plasma generation may be used in the laboratory.（电感耦合型）

58. Figure 3 (b)：a parallel plate structure（平行板结构） of the apparatus
Figure 3 (b)：a parallel plate structure（平行板结构） of the apparatus. A substrate placed on the lower plate having a temperature control device, the radio frequency voltage is applied between the upper and lower parallel plates, so there will be capacitively coupled to the gas discharge in the upper and lower plates and generating plasma.

59. Figure 3 (c) is a diffusion furnace plasma PECVD apparatus is placed a number of parallel plates, the capacitive discharge and the like. It is designed primarily to meet the needs of factory production, increased furnace production. In the PECVD process, the plasma electron impact in the high-speed movement to the neutral gas molecules of the reaction, the reaction will be a neutral gas molecules into fragments or active state readily react. The substrate temperature is generally maintained at about 350 ℃ can obtain good film of SiOx or SiNx can be used as a final passivation layer of the integrated circuit to improve the reliability of integrated circuits.

60. To reduce the reaction temperature required to achieve the purpose of reducing the thermal budget process（工艺热预算）, PECVD in the proportion of components of a CVD process, has become one of the main film deposition means. PECVD reactor in the LSI are used in the process , a mostly also use handle only a substrate of the "single substrate" type designed to ensure uniformity of the deposition surface of the substrate can be controlled within the desired range.

61. MOCVD equipment
Generally MOCVD equipment consists of four parts, and the reaction chamber, the gas pipeline system, gas treatment and electrical control systems.
The devices generally use a multi-chip furnace growth patterns, common MOCVD system is divided into two categories; vertical and horizontal ：
In a conventional vertical device of the sample is placed horizontally, and can be rotated, the reaction gas from the top of the sample perpendicular to the growth chamber into the growth chamber ；
In the conventional horizontal apparatus, the reaction gases are able to enter the sample surface parallel to the growth chamber, not perpendicular to the direction of gas into the sample.

62. Figure 4 ：MOCVD device (vertical reaction chamber)

63. MOCVD equipment
MOCVD equipment to further improve the three main aspects ：
Obtain a large area and high uniformity of film material;
To minimize the dead time for the gas pipe system and the on-off interval to grow the ultra-thin layer of a superlattice structure and material;
MOCVD equipment to the design of a multi-use, flexibility and variability of operating equipment to meet various requirements.

64. Crawler atmospheric pressure CVD device（履带式常压CVD）
To accommodate large-scale production of integrated circuits, while using silane (SiH4), phosphine (PH3) and oxygen in the reaction of 400 ℃ will soon phosphorus silicate glass (SiO2 · xP2O5 complexes), as shown in Figure 5 on the design crawler device shown, the silicon substrate is maintained on the track 400 ℃, the air flow through the bottom was covered with a CVD film. The apparatus may also use a low temperature growth of silicon oxide film or the like.

65. Figure 5： atmospheric pressure CVD device crawler

66. Modular multi-chamber CVD device （模块式多室CVD）
Manufacturing an integrated circuit on a silicon wafer is often necessary to deposit a multilayer film, e.g., SiO2 and Si3N4 deposition of TiN layers and the metal film or a tungsten film. Conventional apparatus is generally a single type batch, ie, only one reaction chamber, single or multiple pieces per batch, handling substrates are exposed to the reaction chamber, the adsorption of atmospheric composition in the reaction chamber wall surface and interior parts you will craft adversely affect the process.
To solve these problems, a multi-chamber CVD apparatus came into being, the modular combination of deposition reaction can be assembled, each of different films deposited at different reaction chamber as shown in Figure 6. Isolation between each reactor using a silicon wafer substrate transfer robot at a low pressure or in vacuum. Can be continuously performed a number of different thin film deposition work, to the ordinary CVD and PECVD together to be a combination of the deposition and dry etching processes together.

67. Figure 6 ：Modular CVD device

68. CVD reactor tank barrel（筒罐式 CVD）
For surface coating of carbide cutting tools （合金刀具）often use this type of device, shown in Figure 7, the gas flowing from top to bottom, it has the advantage of the relationship between the shape of the substrate alloy tool small, all kinds of tools can be deposited simultaneously, and the container is large, you can install a number of thousands.

69. Figure 7 ：barrel tank CVD device

70. Low Pressure CVD Feature Apllications
the first group
Low Pressure CVD
Author: 严 磊
周一苇
Presenter: 常宗涵
Feature
low pressure: 1 mtorr - 1 torr (1 torr≈ Pa) <<1 atm(the standard atmospheric pressure,or 101KPa).
higher gas diffusion rate , thus the mass transport velocity and the velocity of reaction on the surface are higher.
surface reaction often becomes rate limiting step.
2.5mm high,grown in 1day
Apllications
the deposition of thin films on semiconductors usually ranging from a few nanometers to many micrometers, including polysilicon(mainly) for gate contacts, thick oxides used for isolation, doped oxides for global planarization, nitrides and other dielectrics.

71. Low Pressure CVD Some uses of polysilicon
the first group
Low Pressure CVD
Author: 严 磊
周一苇
Presenter: 常宗涵
Some uses of polysilicon
Gate electrodes in MOS devices for high value resistors to insure
good ohmic contact to crystalline silicon.
Diffusion sources to form shallow junctions.
Emitters in bipolar technology.
2.5mm high,grown in 1day

72. Low Pressure CVD Advantages and Disadvantages
the first group
Low Pressure CVD
Author: 严 磊
周一苇
Presenter: 常宗涵
Advantages and Disadvantages
Advantages: • excellent uniformity of thickness , step coverage and purity • simple handling • fewer defects • high reliability, homogeneity of deposited layers and high reproducibility • higher velocity of reaction on the surface.
Disadvantages: • lower deposition rate than APCVD(atmospheric pressure CVD). (we’ll show the association between the pressure and the deposition rate later). • high process temperature around °C. • the excess material after the reaction has taken place is sometimes very harmful.
2.5mm high,grown in 1day

73. Boron Doped ZnO LPCVD Thin film Coating
the first group
Low Pressure CVD
Author: 严 磊
周一苇
Presenter: 常宗涵
Some products by LPCVD
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Gap-fill LPCVD polysilicon
Boron Doped ZnO LPCVD Thin film Coating

74. Low Pressure CVD Low deposition rate when using LPCVD Author: 严 磊 周一苇
the first group
Low Pressure CVD
Author: 严 磊
周一苇
Presenter: 常宗涵
Low deposition rate when using LPCVD
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75. Low Pressure CVD CVD growth rate versus temperature Author: 严 磊 周一苇
the first group
Low Pressure CVD
Author: 严 磊
周一苇
Presenter: 常宗涵
CVD growth rate versus temperature
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76. Low Pressure CVD The effects of lower pressure Author: 严 磊 周一苇
the first group
Low Pressure CVD
Author: 严 磊
周一苇
Presenter: 常宗涵
The effects of lower pressure
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77. Low Pressure CVD The LPCVD process
the first group
Low Pressure CVD
Author: 严 磊
周一苇
Presenter: 常宗涵
The LPCVD process
The LPCVD process has a quartz tube placed in a spiral heater that starts with tube pressure at very low pressure around 0.1 Pa. The tube is then heated to the desired temperature and the gaseous species (“working gas”) is inserted into the tube at the pressure predetermined between Pa. This working gas consists of dilution gas and the reactive gas that will react with the substrate and create a solid phase material on the substrate. After
the working gas enters the tube it spreads out around the hot substrates that are already in the tube at the same temperature. The substrate temperature is extremely important and influences what reactions take place. This working gas reacts with the substrates and forms the solid phase material and the excess material is pumped out of the tube.
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78. Low Pressure CVD Some pictures of LPCVD devices
the first group
Low Pressure CVD
Author: 严 磊
周一苇
Presenter: 常宗涵
Some pictures of LPCVD devices
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Low PressureChemicalVaporDepositionEquipmenthttp://srd.art233.com/userlist/srd/text-1027.html
LPCVD reactor for pyrolitic carbon deposition on graphite foil

79. Plasma Enhanced CVD What is Plasma Enhanced CVD?
the first group
Plasma Enhanced CVD
Author: 卓凌烽
Presenter: 常宗涵
What is Plasma Enhanced CVD?
PECVD is a process where glow-discharge plasma is sustained in s reaction chamber. This technology was developed to meet a demand from the semiconductor industry to have a low temperature process of silicon nitride films for the passivation and insulation of the complete device.
Applications of PECVD
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Plasma Induced Surface Modifications
Plasma Cleaning
Plasma Polymerization
Plasma Reactive Ion Etching
PECVD of SiO2, Si3N4, DLC, and other films

80. Plasma Enhanced CVD compare advantage disadvantage
the first group
Plasma Enhanced CVD
Author: 卓凌烽
Presenter: 常宗涵
compare
advantage
disadvantage
Relatively low temperatures on large areas
Requirement of a vacuum system, and a more sophisticated reactor for plasma
Higher growth rate than thermal CVD
More expensive than the thermally activated CVD system
Higher adhesion
Difficulty in depositing high purity films
Good step coverage
Substrate damaging by strong ion bombardment
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81. Plasma Enhanced CVD PECVD deposition films （1）3SiH4+4NH3 Si3N4+12H2
the first group
Plasma Enhanced CVD
Author: 卓凌烽
Presenter: 常宗涵
（1）3SiH4+4NH Si3N4+12H2
（2）SiH4+2N2O SiO2+2N2+2H2
（3）SiH Si+2H2
（4）(1-x)SiH4+xPH Si1-xPx+[H2]
PECVD deposition films C Pa Ar N
350 ~
250 , 67 2
Plasma C Pa Ar N
350 ~
250 , 67 2
Plasma
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625 ~
500 ,
Plasma C Ar
700 ~
600 ,
Plasma

82. CVD
the first group
Plasma Enhanced CVD
Author: 卓凌烽
Presenter: 常宗涵
2.5mm high,grown in 1day
Using electron energy (plasma) as the activation method to enable deposition at a low temperature and at a reasonable rate

83. Plasma Enhanced CVD plasma in vicinity of substrate:
the first group
Plasma Enhanced CVD
Author: 卓凌烽
Presenter: 常宗涵
plasma in vicinity of substrate:
Plasma breaks up gas molecules
higher reactivity
can use lower temperatures
can use lower pressures
electrons in plasma:
ionize gas to keep plasma going
"activate" gas by dissociation to enhance CVD
typically about 1% of gas is activated
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84. CVD
the first group
Plasma Enhanced CVD
Author: 卓凌烽
Presenter: 常宗涵
An impressive number of different CVD materials present technical interest for a variety of applications. The PECVD is particular interesting due to the relatively low process temperature, allowing for the processing of the complete microelectronic devices.
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85. Metal-organic CVD Uses metal-organic as precursor source
the first group
Metal-organic CVD
Author: 卓凌烽
Presenter: 常宗涵
Uses metal-organic as precursor source
Metal-organic : compounds containing metal atoms bonded to organic radicals
Metal-organic CVD (MOCVD) is a specialized area of CVD, which is a relatively newcomer, as its first reported use was in the 1960s for the deposition of indium phosphide and indium antimonide.
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86. Metal-organic CVD compare advantage disadvantage
the first group
Metal-organic CVD
Author: 卓凌烽
Presenter: 常宗涵
compare
advantage
disadvantage
Deposit a wide range of materials in the form of amorphous, epitaxial and polycrystalline films
Expensive precursors
Not widely available for specific coating
Lower deposition temperature
Most metal-organics are volatile liquids thus accurate pressure control needed
Metal-organic precursors have lower decomposition temperatures than halides, hydrides or halo hydrides
Low thermal stability of precursors due to their polymerization or hydrolysis
Loss of volatility and formation of residue due to ageing
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87. Metal-organic CVD Some about the name of MOCVD
the first group
Metal-organic CVD
Author: 卓凌烽
Presenter: 常宗涵
Some about the name of MOCVD
In the reference, MOCVD also have some other names. Different people prefer different name. All the names refer to the same growth method.
MOCVD (Metal-organic chemical vapor deposition)
OMCVD(Organometallic CVD)
MOVPE (MO vapor phase epistaxis)
OMVPE
AP-MOCVD (Atmosphere MOCVD)
LP-MOCVD (Low pressure MOCVD)
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88. Metal-organic CVD MOCVD growth system Author: 卓凌烽 Presenter: 常宗涵 CVD
the first group
Metal-organic CVD
Author: 卓凌烽
Presenter: 常宗涵
MOCVD growth system
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89. Metal-organic CVD The MOCVD growth system Author: 卓凌烽 Presenter: 常宗涵
the first group
Metal-organic CVD
Author: 卓凌烽
Presenter: 常宗涵
The MOCVD growth system
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90. CVD
the first group
Metal-organic CVD
Author: 卓凌烽
Presenter: 常宗涵
MOCVD is presently the major processes for the production of optoelectronic thin films, which is capable of meeting the extremely stringent property requirements of the new designs.
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91. Chemical Vapor Deposition
CVD
the first group
Chemical Vapor Deposition
NO.1
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