What question did this study set out to answer?

The aim is to investigate how high temperature pretreatment affects dislocation density in GaN films grown by HVPE.

April 12, 2026Open Access

Dislocation reduction in HVPE GaN via high temperature pretreatment of MOCVD-GaN/sapphire substrate

Key Points

The aim is to investigate how high temperature pretreatment affects dislocation density in GaN films grown by HVPE.
Fabrication of decomposition pits on MOCVD-GaN/sapphire substrate through high temperature pretreatment.
Characterization of substrate morphologies using scanning electron microscopy and transmission electron microscopy.
Integration of optimized HTP process with GaN growth via HVPE.
Evaluation of dislocation density using cathodoluminescence and molten KOH–NaOH eutectic etching.
Dislocation density in HVPE GaN reduced to 10^5 cm−2.
Optimization of the high temperature pretreatment process confirmed.
Effective reduction of dislocations enhances GaN quality.

Abstract

In this paper, decomposition pits on the MOCVD-GaN/sapphire substrate were fabricated by the high temperature pretreatment (HTP) process for the purpose of reducing dislocations in the subsequently grown GaN by hydride vapor phase epitaxy (HVPE). The impact of atmosphere, temperature, and time during HTP on the substrate morphologies was characterized by scanning electron microscopy and transmission electron microscopy. The optimum HTP process was confirmed and integrated with the GaN growing process by HVPE. Cathodoluminescence and molten KOH–NaOH eutectic etching were used to evaluate the dislocation density of HVPE GaN. The dislocation density was reduced by orders of magnitude to 105 cm−2. The results indicated that the high temperature pretreatment process can effectively reduce dislocations of HVPE GaN.

Dislocation reduction in HVPE GaN via high temperature pretreatment of MOCVD-GaN/sapphire substrate

Key Points

Abstract

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