Direct Observation of Stress Relaxation Process in 4H-SiC Homoepitaxial Layers via In Situ Synchrotron X-Ray Topography

Jian Qiu Guo; Yu Yang; Balaji Raghothamachar; Michael Dudley; Swetlana Weit; Andreas N. Danilewsky; Patrick J. McNally; Brian R. Tanner

doi:10.4028/www.scientific.net/MSF.924.176

Paper Titles

Immobilization Phenomenon of Partials Surrounding Double Shockley Stacking Faults in Heavily Nitrogen Doped 4H-SiC Crystal with Thermal Anneal
p.160

Influence of Triangular Defects on the Electrical Characteristics of 4H-SiC Devices
p.164

Origin Analysis and Elimination of Obtuse Triangular Defects in 4° Off 4H-SiC Epitaxy
p.168

In Situ Synchrotron X-Ray Topography Observation of Double-Ended Frank-Read Sources in PVT-Grown 4H-SiC Wafers
p.172

Direct Observation of Stress Relaxation Process in 4H-SiC Homoepitaxial Layers via In Situ Synchrotron X-Ray Topography
p.176

X-Ray Topography Analysis of 4H-SiC Crystals Grown by the High-Temperature Gas Source Method
p.180

Analysis of Compensation Effects in Aluminum-Implanted 4H-SiC Devices
p.184

Comparison of Conduction Mechanisms in Heavily Al-Doped 4H-SiC and Heavily Al- and N-Codoped 4H-SiC
p.188

Modeling and Simulation of Electrical Activation of Acceptor-Type Dopants in Silicon Carbide
p.192

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Direct Observation of Stress Relaxation Process in 4H-SiC Homoepitaxial Layers via In Situ Synchrotron X-Ray Topography

Abstract:

During 4H silicon carbide (4H-SiC) homoepitaxy and post-growth processes, the development of stress relaxation has been observed, in which interfacial dislocations (IDs) are formed at the epilayer/substrate interface, relaxing the misfit strain induced by the nitrogen doping concentration difference between the epilayer and substrate. It is widely believed that an interfacial dislocation is created by the glide of a mobile segment of a basal plane dislocation (BPD) in the substrate or epilayer towards the interface, leaving a trailing edge component right at the interface. However, direct observation of such mechanisms has not been made in SiC before. In this work, we present an in situ study of the stress relaxation process, in which a specimen cut from a commercial 4H-SiC homoepitaxial wafer undergoes the stress relaxation process during a high-temperature heat treatment while sequential synchrotron white beam X-ray topographs were recorded simultaneously. Based on the dynamic observation of this process, it can be concluded that thermal stress plays a role in the relaxation process while the increased misfit strain at elevated temperature most likely drives the formation of an interfacial dislocation.