Dislocations in (011)-oriented vertical Bridgman $\beta$-Ga$_2$O$_3$ substrates

TL;DR

This study investigates dislocation structures in (011)-oriented $eta$-Ga$_2$O$_3$ substrates grown by vertical Bridgman, using advanced X-ray techniques to understand defect formation affecting device quality.

Contribution

It provides detailed characterization of dislocations and domain boundaries in $eta$-Ga$_2$O$_3$ substrates, linking defect structures to growth processes and device implications.

Findings

Dislocations on (001) plane form arrays linked to domain boundaries.

Dislocations on (011) plane differ from those causing pits on epilayers.

Reticulography reveals domain boundary misorientations around 1E-5 rad.

Abstract

Dislocation in (011)-oriented $\beta$-Ga$_2$O$_3$ substrates grown by the vertical Bridgman method was investigated using X-ray topography (XRT), combined with X-ray reticulography. Transmission XRT reveals dislocations lying on the (001) plane and extending along [010], forming arrays associated with domain boundaries. Dislocations on the (011) plane were also identified but differ from those responsible for line-shaped pits on (001) epilayers. Reflection XRT shows good agreement with transmission XRT and enables classification of dislocation types based on contrast features. Reticulography confirms domain boundaries with misorientation on the order of 1E-5 rad, providing insight into defect formation relevant to epi-growth and device performance.