Modified high temperature vapor phase epitaxy for growth of GaN films

The high temperature vapor phase epitaxy (HTVPE) uses ammonia and thermally evaporated, elemental gallium as precursors for the growth of GaN films. This paper investigates the HTVPE using numerical modeling of the gallium vapor transport and systematical growth experiments. The presented growth setup allows a flexible control of the growth process and variation of growth parameters in a wide range. Based on simulation results, the impact of the gallium melt temperature, the gas flow in the reactor and the reactor pressure on the gallium vapor transport is studied in detail. Experimental growth rates as function of the reactor pressure and the melt temperature are compared with the numerical simulation. The influence of hydrogen in the carrier gas on the properties of the HTVPE GaN layers is discussed.