Vapor phase growth of GaN using GaN powder sources and thermogravimetric investigations of the evaporating behaviour of the source material

Abstract

The growth of GaN from the vapor phase is a promising technique for producing both bulk GaN crystals and GaN layers. For establishing a growth method from the vapor phase the source material and reactor setup are of great importance. Highly pure and self synthesized GaN powder was chosen as source material. The evaporation behaviour of the GaN powder was studied by means of thermogravimetry (TG). A vertical growth reactor was set up according to the results of numerical simulations of the temperature distributions and flow patterns. Freely nucleated GaN platelets of some millimetres in length were grown. Furthermore, thin GaN layers were deposited directly on a sapphire substrate. This nucleation layer was successfully overgrown by low pressure solution growth.

Thermodynamic properties of gallium nitride

“…Furthermore, there is ample evidence that liquid Ga catalyzes the decomposition of GaN [5][6][7][8][9]. In fact, in their study, Pisch and Schmidt-Fetzer [6] showed that the rate-limiting step for the decomposition of GaN is the formation of liquid Ga.…”

Erlangen—An Important Center of Crystal Growth and Epitaxy: Major Scientific Results and Technological Solutions of the Last Four Decades

“…At the very beginning the low‐pressure solution growth (LPSG) technique and the sublimation method were developed at IISB to evaluate whether these crystal growth techniques would have the potential to serve as industrial production methods for growing GaN bulk crystals. Very quickly it became clear, that the sublimation method is not suitable for such purpose as the GaN powder decomposes incongruently, such that only liquid Ga remains after a short period of time and additional transport agents would then be needed to control the transport of Ga species from the source to the growth interface . Therefore, no principal advantage exists compared to the mostly used hydride vapor phase epitaxy (HVPE) technique.…”

Simulation of Single Crystal Growth: Heat and Mass Transfer

“…Сублимационный 6 рост (также -конденсация из паровой фазы, модифицированный метод Леви), разработанный Ю. М. Таировым и В. Ф. Цветковым [66], используется для получения кристаллов SiC и AlN [41,67,68,69], ZnO [70], волокон AlN [71], других нитридов, например, нитрида титана [72]. Сублимационный рост кристаллов GaN менее успешен [73] равновесное давление азота над поверхностью GaN на шесть порядков выше, чем над AlN [74].…”