1. 전자물리 Chap. 1 Crystal properties and growth of Semiconductor

2. A semiconductor is a solid material that has electrical conductivity in between a conductor and an insulator. Semiconductors are very similar to insulators. The two categories of solids differ primarily in that insulators have larger energy band gaps that elecrrons must acquire to be free to move from atom to atom.

3. Periodic table where semiconductor occur IIIIIIVVVI B Boron C Carbon N Nitrogen O Oxygen Al Aluminum Si Silicon P Phosphorus S Sulfur Zn Zinc Ga Galium Ge Germanium As Arsenic Se Selenium Cd Cadmium In Indium Sn Tin Sb Antimony Te Tellurium

4. -Si and atomic number 14 14. The atomic mass is 28.0855. - Silicon, like carbon and other group IV elements form face-centered diamond cubic crystal structure. - Silicon, in particular, forms a face-centered cubic structure with a lattice spacing of 5.430710 A (0.5430710 nm).

5. Si Crystal structure : diamond cubic Magnetic ordering: diamagnetic Electric resistivity : (20 °C) 10 3] Ω·m] Thermal conductivity: (300 K) 149 W·m −1 ·K −1 Thermal expansion : (25 °C) 2.6 µm·m −1 ·K −1 Speed of sound : (thin rod) (20 °C) 8433 m/s Young’s modulous: 185 Gpa Shear modulous : 52 Gpa Bulk modulous :100 GPa Band gap energy at 300 K 1.12eV

6. Some electrical conductivities of metal Electrical Conductivity (S·m -1 ) Temperatur e(°C) Notes Silver63.01 × 10 6 20Highest electrical conductivity of any known metal Copper59.6 × 10 6 20 Annealed copperrr 58.0 × 10 6 20Referred to as 100% IACS or International Annealed Copper Standard. The unit for expressing the conductivity of nonmagnetic materials by testing using the eddy-current method. Generally used for temper and alloy verification of Aluminum. Gold45.2 × 10 6 20Gold is commonly used in electrical contacts Aluminum37.8 × 10 6 20 Seawater523Refer to http://www.kayelaby.npl.co.uk/general_physics/2_7/2_7_9.html for more detail as there are many variations and significant variables for seawater.http://www.kayelaby.npl.co.uk/general_physics/2_7/2_7_9.html 5(S·m -1 ) would be for an average salinity of 35 g/kg at about 23(°C) Copyright on the linked material can be found here http://www.kayelaby.npl.co.uk/copyright/ http://www.kayelaby.npl.co.uk/copyright/ Drinking water 0.0005 to 0.05This value range is typical of high quality drinking water and not an indicator of water quality Deionized water 5.5 × 10 -6 changes to 1.2 × 10 -4 in water with no gas present

7. Semiconductor materials Element : Si, Ge IV compoinds : SiC, SiGe III-V compounds: AIP, AlAs, AlSb, GaN,GaP, GaAs, GaSb, InP, InAs, InSb II-VI: SnS, ZnSe, ZnTe, CdS, CdSe, CdTe LED(GaN, GaP, GaAs), Three-elements(GaAsP, InGaAsP), Fluorescent(II-VI, ZnS), Light detector(InSb, CdSe), PbTe, HgCdTe, Si, Ge) IIIIIIVVVI B Boron C Carbon N Nitrogen O Oxygen Al Aluminum Si Silicon P Phosphorus S Sulfur Zn Zinc Ga Galium Ge Germanium As Arsenic Se Selenium Cd Cadmium In Indium Sn Tin Sb Antimony Te Tellurium

8. In Semiconductor production, doping is the process of intentionally introducing impurities into an extremely pure (also referred to as intrinsic) semiconductor in order to change its electrical properties. The number of dopant atoms needed to create a difference in the ability of a semiconductor to conduct is very small. Where a comparatively small number of dopant atoms are added (of the order of 1 every 100,000,000 atoms) then the doping is said to be low, or light. Where many more are added (of the order of 1 in 10,000) then the doping is referred to as heavy, or high. This is often shown as n+ for n-type dopant or p+ for p- type doping.

9. Materials Single crystal amorphous solid Polycrystalline Liquid crystal

10. Crystalline: Single crystal A single crystal, also called monocrystal, is a crystalline solid in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample, with no grain boundaries. Insulin crystals Gallium, a metal that easily forms large single crystals Quartz crystal Silicon

11. amorphous solid An amorphous solid is a soild in which there is no long-range order of the positions of the atoms. (Solids in which there is long-range atomic order are called crystalline solids or morphous. Most classes of solid materials can be found or prepared in an amorphous form. For instance, common window glass is an amorphous ceramic, many polymers (such as polystyrene) are amorphous, and even foods such as cotton candy are amorphous solids. The amorphous structure of glassy Silica (SiO 2 ). No long range order is present, however there is local ordering with respect to the tetrahedral arrangement of Oxygen (O) atoms around the Silicon (Si) atoms.

12. Polycrystalline Polycrystalline materials are solids that are composed of many crystallites of varying size and orientation. The variation in direction can be random (called random texture) or directed, possibly due to growth and processing conditions. Fiber texture is an example of the latter. Almost all common metals, and many ceramics are polycrystalline. The crystallites are often referred to as grains, however, powder grains are a different context. Powder grains can themselves be composed of smaller polycrystalline grains.

13. In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. A crystal structure is composed of a motif, a set of atoms arranged in a particular way, and a lattice. Motifs are located upon the points of a lattice, which is an array of points repeating periodically in three dimensions. The points can be thought of as forming identical tiny boxes, called unit cells, that fill the space of the lattice. The lengths of the edges of a unit cell and the angles between them are called the lattice parameters. The symmetry properties of the crystal are embodied in its space group. A crystal's structure and symmetry play a role in determining many of its properties, such as cleavage, electronic band structure, and optical properties. Crystal Lattice

14. Two-dimensional lattice

15. The Bravais lattices are the distinct lattice types, which when repeated can fill the whole space. The lattice can therefore be generated by three unit vectors, and a set of integers k, l and m so that each lattice point, identified by a vector, can be obtained from: (2.2.1) The construction of the lattice points based on a set of unit vectors is illustrated. The construction of lattice points using unit vectors

16. In two dimensions, there are five distinct Bravais lattices, while in three dimensions there are fourteen. The five Bravais lattices of two-dimensional crystals: (a) square, (b) rectangular, (c) centered rectangular, (d) hexagonal and (e) oblique

17. Bravais lattices of two-dimensional crystals a1 and a2 are the magnitudes of the unit vectors and  is the angle between them

18. Bravais lattices of three-dimensional crystals The fourteen lattices of three-dimensional crystals are classified where a1, a2 and a3 are the magnitudes of the unit vectors defining the traditional unit cell and a, b and g are the angles between these unit vectors

19. Cubic Lattice The cubic lattices are an important subset of these fourteen Bravais lattices since a large number of semiconductors are cubic. The three cubic Bravais lattices are the simple cubic lattice, the body- centered cubic lattice and the face-centered cubic lattice as shown in Figure. Since all unit vectors identifying the traditional unit cell have the same size, the crystal structure is completely defined by a single number. This number is the lattice constant, a. The simple cubic (a), the body-centered cubic (b) and the face centered cubic (c) lattice.

20. The seven lattice systems These lattice systems are a grouping of crystal structures according to the axial system used to describe their lattice. Each lattice system consists of a set of three axes in a particular geometrical arrangement. There are seven lattice systems. They are similar to but not quite the same as the seven crystal systems and the six crystal families.

22. Miller indices Crystal planes of a crystal are characterized by their Miller indices. The Miller indices are defined as the smallest possible integers, which have the same ratios as the inverse of the intersections of a given plane with a set of axis defined by the unit vectors of that crystal. The intersections between the plane and the axis occur at p, q, and r. The corresponding Miller indices are therefore therefore where A is an integer chosen such that the Miller indices are the smallest possible integers. It should be noted that the resulting Miller indices are the same for all parallel planes of atoms in a crystal.

23. Intersections of a plane and the x, y and z axes, as used to determine the Miller indices of the plane

24. Lattice plane

25. hexagonal

26. Common semiconductor crystal structures The most common crystal structure among frequently used semiconductors is the diamond lattice Each atom in the diamond lattice has a covalent bond with four adjacent atoms, which together form a tetrahedron. This lattice can also be formed from two face-centered-cubic lattices, which are displaced along the body diagonal of the larger cube in Figure by one quarter of that body diagonal. The diamond lattice therefore is a face-centered-cubic lattice with a basis containing two identical atoms. The diamond lattice of Si(silicon) and Ge(germanium)

27. zinc-blend crystal structure Compound semiconductors such as GaAs and InP have a crystal structure that is similar to that of diamond. However, the lattice contains two different types of atoms. Each atom still has four covalent bonds, but these are bonds to atoms of the other type. This structure is referred to as the zinc-blend lattice, named after zinc-blend crystal (ZnS) as shown in Figure The zinc-blend crystal structure of GaAs and InP. The cubic crystals are characterized by a single parameter, the lattice constant a,

28. Production : Starting material Si Silicon is commercially prepared by the reaction of high-purity silica with wood, charcoal, and coal, in an electric arc furnace using carbon electrodes. At temperatures over 1,900 ℃, the carbon reduces the silica to silicon according to the chemical equation –SiO2 + C → Si + CO2. –SiO2 + 2C → Si + 2CO.

29. Growth of semiconductor crystals The first transistor was invented at Bell Laboratories on December 16, 1947 by William Shockley (seated at Brattain's laboratory bench), John Bardeen (left) and Walter Brattain (right). This was perhaps the most important electronics event of the 20th century, as it later made possible the integrated circuit and microprocessor that are the basis of modern electronics. Prior to the transistor the only alternative to its current regulation and switching functions (TRANSfer resISTOR) was the vacuum tube, which could only be miniaturized to a certain extent, and wasted a lot of energy in the form of heat.

30. Form of metallurgical grade Si (MGS) In the Siemens process, high-purity silicon rods are exposed to trichlorosilane at 1150 °C. The trichlorosilane gas decomposes and deposits additional silicon onto the rods, enlarging them according to chemical reactions like –2 HSiCl3 → Si + 2 HCl + SiCl4. Silicon produced from this and similar processes is called polycrystalline silicon. Polycrystalline silicon typically has impurity levels of less than 10 −9. Metallurgical grade Si (MGS) : thousand parts pet million ppm 1x10 16 cm -3 Electronical grade Si (EGS) : : parts pet billion ppb 1x10 13 cm -3 In 2006 Renewable Energy Corporation (REC) announced construction of a plant based on fluidized bed technology using silane. –3SiCl4 + Si + 2H2 → 4HSiCl3 –4HSiCl3 → 3SiCl4 + SiH4 –SiH4 → Si + 2H2

31. A diagram of a fluidized bed, including a particle force balance and distributor plate designs

32. Growth of Single crystal: Czochralski process

34. Wafer

35. Epitaxial Growth Epitaxy refers to the method of depositing a monocrystalalline film on a monocrystalline(single crystal) substrate. The deposited film is denoted as epitaxial film or epitaxial layer. The term epitaxy comes from the Greek roots epi, meaning "above", and taxis, meaning "in ordered manner". It can be translated "to arrange upon".

36. Molecular Beam Epitaxy

37. MBE Molecular beam epitaxy takes place in high vacuum or ultra high vacuum (10 −8 Pa). The most important aspect of MBE is the slow deposition rate (typically less than 1000 nm per hour), which allows the films to grow epitaxially. The slow deposition rates require proportionally better vacuum to achieve the same impurity levels as other deposition techniques.