Structural characterization of defects in EFG- and HVPE-grown <i>β</i> -Ga <sub>2</sub> O <sub>3</sub> crystals
Osamu Ueda, Makoto Kasu, Hiroshi Yamaguchi
Abstract
Abstract This paper reviews the status of characterization of defects in β -Ga 2 O 3 crystals grown by edge-defined film-fed growth and hydride vapor phase epitaxy using chemical etching, scanning electron microscopy, focused ion beam scanning ion microscopy, X-ray topography (XRT), and transmission electron microscopy (TEM). The observed defects are classified into four types: dislocations, stacking faults (SFs), twins, and plate-like nanovoids (PNVs). First, we present the detailed characterization of dislocations in the crystal by chemical etching, XRT, and TEM, and discuss possible slip systems. Next, we describe XRT analyses of two types of SFs: SFs 1 lying on the ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mn>2</mml:mn> <mml:mo>¯</mml:mo> </mml:mover> <mml:mn>01</mml:mn> </mml:math> ) plane and SFs 2 on the (111) and ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>1</mml:mn> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo>¯</mml:mo> </mml:mover> <mml:mn>1</mml:mn> </mml:math> ) planes. We describe the results for twins found in crystals via high-resolution TEM and electron diffraction analysis, and PNVs corresponding to etch pits on the (010) plane. Finally, we discuss possible generation mechanisms of the defects and their influence on device characteristics.