# Two modes of HVPE growth of GaN and related macrodefects

## TL;DR

This study compares two GaN growth modes via HVPE, analyzing their surface quality, defect formation, and stress, and demonstrates a combined approach to optimize film quality.

## Contribution

It introduces a combined growth strategy using LT and HT modes to produce crack-free GaN films with improved surface quality.

## Key findings

- HT mode yields smooth surfaces but high stress and cracking.
- LT mode results in rough surfaces with high V-defect density but no cracks.
- Combining LT and HT modes reduces defects and prevents cracking.

## Abstract

GaN films with thickness up to 3 mm were grown by halide vapour phase epitaxy method. Two growth modes were observed: the high temperature (HT) mode and the low temperature (LT) mode. Films grown in HT mode had smooth surface, however the growth stress was high and caused cracking. Films grown in LT mode had rough surface with high density of V-defects (pits), however such films were crack-free. The influence of growth parameters on the pit shape and evolution was investigated. Origins of pits formation and process of pit overgrowth are discussed. Crack-free films with smooth surface and reduced density of pits were grown using combination of the LT and HT growth modes.