1. Work Package 2 Exploring Novel Materials Systems
Sérgio Miranda
Djibril Ndiack Faye
Victor Alarcon Diez

2. Purpose Exploring Novel Materials Systems Semiconductors
SiC, Ge, AlGaN,…
Devices (electronic)

3. Rutherford Backscattering Spectroscopy (RBS)
Ion beam technique
Stopping powerEnergy loss
Scattering cross section
(Chu, Wei-kan; Mayer, James W.; Nicolet 1978)
Information:
Composition
Depht
Structure  Damage
(Schmaus & Vickridge, 2005)

4. RBS-channelling SrTO3 Impurities measures
Damage due to ion-material interaction

5. Large Area Charged Particle Detector
Single detectors area are between 25 mm2 and 300 mm2; our segdet area is 900mm2  area between 36 and 3 times bigger!!
Pa represent how quick the material goes to the amorphization state.

6. Segmentation (H. Spieler, Semiconductor Detector Systems, 2005)
particle rate less counts per segment, therefore data more manageable
Capacitance decrease so it works as a filter  less electrical noise
Mass/depth ambiguity  different mass emerging from different depth can be collected by detector with same energy
(H. Spieler, Semiconductor Detector Systems, 2005)
(G. Dearnaley and D.C. Northrop, semiconductor counters for nuclear radiations, 1964)

7. Segmented Detector Energy Resolution

8. Segmented Detector Aplication Example
Determination of Mn in Ga1-xMnxAs
1.8MeV 4He+ 35mC

9. Digital Pulse Processing Data Acquisition
High number of detectors
16 Channels
Low price
Comfortable equipment
PC software application
More information
High number of extracted data
Analogue

10. Digital Pulse Processing: Energy resolution
Experiment: alpha particle at 1.5 MeV in Au monolayer over TiO2 substrate

11. Future Studies Damage Another Ion beam technique: ERDA
Polymers: RBS
RBS-channelling microbeams
Another Ion beam technique: ERDA
Small component amount

12. XRD What is X-Ray-Diffraction? X-Ray Source Sample
The atomic planes of a crystal cause on incident beam of X-rays to interfere with one another as they leave the crystal. The phenomenon is called X-ray diffraction.
X-Ray Source
Sample
Monochromator
detector

13. Bragg’s Law and Diffraction: How waves reveal the atomic structure of crystals?
Diffraction occurs only when Bragg’s Law is satisfied Condition for constructive interference (X-rays 1 & 2) from planes with spacing d
Peak position 2theta
BRAGG’s EQUATION: n = 2d Sin d 
dSin
The path difference between ray 1 and ray 2 = 2d Sin
For constructive interference: n = 2d Sin
Ray 1
Ray 2
Deviation = 2

14. Why XRD? To identify crystalline phases and orientation
To determine structural properties:
Lattice parameters (10-4Å),
strain, grain size,
To measure thickness of thin films
To determine atomic arrangement

15. AlGaN?
White-light–emitting devices requires the introduction of optically active REs elements
Ion implantation is an attractive technique.
Unfortunately generates structural damage,
Degrading the properties of the materials
A good understanding of the damage of AlxGa1-xN alloys implanted by rare earth elements:
XRD,RBS, to study the mechanism of damage formation
improve of Rare Earth luminescence efficiency in AlxGa1-xN alloys

16. XRD strain evolution

17. SiC and Ge Materials Property @ 300 K Si 4H-SiC Ge 1.1 3.2 0.67 0.3
Band gap (eV)
1.1
3.2
0.67
Breakdown field (106 V/cm)
0.3
3 - 5 1
Electron mobility (cm2/(V*s))
1400
900
3900
Hole mobility (cm2/(V*s))
450
120
1900
Electron saturated drift velocity (106 cm/s) 10
8 - 22
Thermal conductivity (Watts/cm2 K)
1.5
0.58
Ge → Fast processor devices
Electrical contacts
SiC → Power devices

18. SiC SiC Ni Good performance at higher Temperature Ni2Si annealing
hypothesis:
1- C vacancies
2- C precipitates
3 – Silicides
1º - Ni deposition
2º - SiC dissociation
3º - C out-diffuses to surface
4º - Silicide formation
5º - C accumulates at interface → precipitates
6º - Low resistivity (graphitisation)
Temperature
Jung et al., Journal of The Electrochemical Society, 158 (5) H551-H553 (2011)
Cao et al., Materials Science and Technology, vol. 22, 10 (2006) 1227

19. Ge Low formation temperature Low resistivity
______________________________________________________________
Poor thermal stability (400 ºC):
Agglomeration
Oxidation Ni
NiGe Ge Ge Ni
Pd or Pt
Pt2NiGe
PtGe
Phase formation or not → similar results (low at.%)?
Higher Pt content better → Not true for Pd! Ge
Kang et al., IEEE Transactions on Nanotechnology, vol. 11, no. 4, 2012
Zhang et al., Recent advances in electronics, hardware, wireless and optical communications, 2010
Zhang et al., IEEE Transactions on Nanotechnology, vol. 9, no. 2, 2010
Majhi et al., Electrochemical and Solid-State Letters 12 (11), H402-H404, 2009

20. C interlayer affect contact performance? The diffusion of elements;
SiC:
C interlayer affect contact performance?
The diffusion of elements;
Phase formation and texture;
Ge:
How do Pt or Pd stabilize contacts?

21. X-ray diffraction → texture
Strong
texture No
texture

22. Preliminary results: XRD real time
Ge - realtime X-ray diffraction
Preliminary results: XRD real time
20nm Ni
0.3nm Pt + 20nm Ni
HEX
ɛ-Ni5Ge3
HEX
ɛ-Ni5Ge3
NiGe
NiGe Ni Ni
1nm Pt + 20nm Ni
4nm Pt + 20nm Ni
Pt germanide
NiGe
NiGe Ni Ni

23. Ge - realtime X-ray diffraction
20nm Ni
0.3nm Pd + 20nm Ni
HEX
ɛ-Ni5Ge3
HEX
ɛ-Ni5Ge3
NiGe
NiGe Ni Ni
1nm Pd + 20nm Ni
4nm Pd + 20nm Ni
HEX
ɛ-Ni5Ge3
NiGe
NiGe Ni
?PdGe + Ni3Ge

24. SiC – realtime X-ray diffraction
20nm Ni
SiC
Ni23Si2 + Ni74Si26
Ni2Si Ni
Ni31Si12
6nm Ni
SiC
Ni74Si26
Ni2Si + C Ni
Ni31Si12

25. Future work Confirm phases/textures detected
Elements diffusion – Ion Beam techniques
SiC – Determine critical thickness
Ge – Explore differences Pt or Pd

26. Modification damage Electrical contacts Detection
Work Package 2 Exploring Novel Materials Systems - Semiconductors
Modification
damage
Electrical
contacts
Detection

27. A BIG thank you. SPRITE and Partners. Promotors
A BIG thank you SPRITE and Partners Promotors Universities and Institutes Karen, Francine and Eduardo YOU