Structural and electrical anisotropies of Si-doped a-plane (11–20) GaN films with different SiN_x interlayers

Abstract

The effects of different SiN x interlayers on the structural and electrical properties of nonpolar Si-doped a-plane (11-20) GaN films grown on r-plane (1-102) sapphire were investigated. The surface roughness depends strongly on the SiN x coverage, deposition temperature and number of SiN x layers. The in-plane anisotropy of on-axis x-ray rocking curves (XRCs) (full width at half-maximum) was significantly decreased by the introduction of multiple SiN x -treated GaN interlayers, indicating coherently scattering domains of uniform size. Off-axis XRC measurements were also employed to investigate the effects on the mosaic twist corresponding to edge dislocation and the I 1 -type basal-plane stacking fault (BSF) density. Hall effect measurement showed that the electrical conductivity was the highest when multiple SiN x /GaN interlayers were employed. The measured sheet resistances (R sh ) along the c-axis were higher than those along the m-axis. These anisotropic conductivities could be explained by BSFs acting as carrier scattering centers. The ratios of R sh along the two in-plane orientations also correlated well with the BSF densities.

Optimizing GaN () hetero‐epitaxial templates grown on () sapphire

“…SiN x ILs have also been shown to reduce dislocations and BSFs in the growth of () and () () GaN templates. The SiN x IL induces islanding and subsequent 3D growth, similar to observed for the growth of (0001) GaN, e.g., .…”

Anisotropic electrical conductivity of surface-roughened semipolar $(11\bar{2}2)$ GaN films by photochemical etching

“…18) The authors of the present study previously reported anisotropy in the lateral conductivity of faulted nonpolar a-plane GaN films as well as in s-GaN. [17][18][19] The in-plane directional dependence of the sheet resistances of nonpolar and semipolar GaN films could be explained by carrier scattering caused by basal-plane stacking faults (BPSFs). BPSFs with a very thin zinc blende layer, which are embedded in wurtzite GaN matrix, can be dominant scattering centers for charged carriers.…”

“…Researches have previously reported directionally-dependent carrier transport in highly faulted nonpolar and semipolar GaN films. [15][16][17][18][19][20][21][22] This anisotropic electrical conductivity is believed to be associated with carrier scattering phenomena from BPSFs. In this paper, we focused on how modifying the surface of semipolar ð11 22Þ GaN (s-GaN) films would affect the contact properties and the anisotropic electrical conductivity.…”

Effect of Basal-plane Stacking Faults on X-ray Diffraction of Non-polar (1120) a-plane GaN Films Grown on (1102) r-plane Sapphire Substrates

“…Therefore, at low temperatures, BSFs exhibit characteristic luminescence features in the region of 3.42~3.44 eV, and this finding indicates an effective radiative recombination channel in non-polar GaN-based structures [13,14]. Moreover, BSFs have also been proposed as the origin of anisotropic electrical conductivity along in-plane orientations in non-polar GaN films [15][16][17]. Consequently, the BSFs can significantly affect structural, electrical, and optical properties of non-polar GaN-based optoelectronic and/or electronic devices.…”