In-Situ Monitoring of GaN Growth by Hydride Vapor Phase Epitaxy

Abstract

In‐situ reflectivity measurements of the growth surface during deposition in a Hydride Vapor Phase Epitaxy system are presented. The GaN growth rate increases linearly with the HCl flow and increases monotonically with the ammonia flow. Following the replacement of the carrier gas nitrogen by hydrogen, the growth rate initially increases, passes through a maximum at a H2 concentration of 0.15 and then decreases.

Stress control in GaN/sapphire templates for the fabrication of crack-free thick layers

“…Thick GaN layers were then grown in a commercial Aixtron horizontal HVPE reactor on the GaN/sapphire templates prepared by MOVPE. This reactor is equipped with a home made in situ reflectance monitoring apparatus [6]. The evolution of the reflectivity signal allows a real time control of the growth rate and the critical thickness for the formation of cracks is detected by an abrupt change of the signal intensity.…”

a-plane GaN grown on r-plane sapphire substrates by hydride vapor phase epitaxy

“…Samples were grown in a commercial Aixtron horizontal HVPE reactor equipped with a home-made in situ reflectance monitoring apparatus [9]. For the single-step HT growth procedure, the substrate temperature is first increased up to $1100 1C in NH 3 and H 2 ambient.…”

Surface chemistry and transport effects in GaN hydride vapor phase epitaxy

“…The growth rate at the center of the wafer was in-situ monitored by a laser reflectometer operating at 670 nm (see Ref. [17] for details).…”

“…The changes in the reactive species flow rates were compensated by countervariations of the corresponding N 2 flow rates in such a way as to keep the total gas flow rates through all the injectors constant. All predictions of the GaN growth rate discussed below are referred to the center of the wafer where it was monitored by the laser reflectometer [17]. Comparison of the computations with the experimental data is shown in Figs.…”

“…For this purpose, detailed data on the GaN growth rate as a function of growth conditions, obtained by in situ laser reflectometry [17], play an essential role. They allow the refinement of the HVPE model and the assessments of the factor most critical for this growth technique.…”