Evaluation of Vertical Coherence Length, Twist and Microstrain of GaAs / Si Epilayers Using Modified Williamson-Hall Analysis

Authors Ravi Kumar1, Tapas Ganguli2, Vijay Chouhan1,4, V.K. Dixit1, Puspen Mondal2, A.K. Srivastava2, C. Mukherjee3, T.K. Sharma1

1 Semiconductor Physics & Devices Laboratory, Raja Ramanna Centre for Advanced Technology, Indore - 452013, India

2 Indus Synchrotron Utilisation Division, Raja Ramanna Centre for Advanced Technology, Indore - 452013, India

3 Mechanical & Optical Support Section, Raja Ramanna Centre for Advanced Technology, Indore - 452013, India

4 Currently at High energy accelerator research organization (KEK), Tsukuba 305- 0801, Japan

Е-mail ravi@rrcat.gov.in, tarun@rrcat.gov.in
Issue Volume 6, Year 2014, Number 2
Dates Received 05 May 2014; published online 20 June 2014
Citation Ravi Kumar, Tapas Ganguli, Vijay Chouhan, et al., J. Nano- Electron. Phys. 6 No 2, 02010 (2014)
PACS Number(s) 61.05.cp, 81.05.Ea
Keywords HRXRD (3) , GaAs / Si (2) , Anti Phase domain, Microstructure (21) , Williamson-Hall analysis.
Annotation Modified Williamson-Hall (WH) analysis is used to determine the reliable values of the microstructures for Zincblende epilayers grown on non-polar substrates. Systematic high resolution X-ray diffraction (HRXRD) experiments are performed for several skew symmetric reflections which enable an accurate measurement of the values of vertical coherence length (VCL) and microstrain of GaAs epilayers grown on Si. Furthermore, a simple method based on the orientation of Burgers vector is proposed for estimating the ratio of tilt and twist. In this method, the twist can be found easily once tilt is known. It is rather quick and the measured values of twist are very similar to those which are otherwise estimated by acquiring numerous HRXRD scans along with tedious fitting procedures. Presence of 60 mixed dislocations is confirmed from the cross sectional high resolution transmission electron microscope images of GaAs / Si samples. Furthermore, the estimated value of VCL is equivalent to the layer thickness measured by the surface profiler.

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