Growth of thick AlN layers by hydride vapor-phase epitaxy

Abstract

Growth of AlN on sapphire (0 0 0 1) substrates by hydride vapor-phase epitaxy (HVPE) was investigated using AlCl 3 and NH 3 as source gases in the temperature range from 950 to 1100 °C. It was found that the full-width at half-maximum (FWHM) values of the X-ray diffraction (XRD) rocking curves of the (0 0 0 2) and ( 1 0 1 ¯ 0 ) planes of the c-axis oriented AlN layers decreased with increasing growth temperature. An AlN layer showing a mirror-like surface could be grown at 1100 °C with a growth rate of 1.7 μm/h. Growth rate was found to increase with increasing AlCl 3 input partial pressure and with decreasing distance ( L) between the end of the AlCl 3 injection nozzle and the sapphire substrate. The growth rate reached 122 μm/h with an AlCl 3 input partial pressure of 2.0×10 −3 atm and L = 25 mm but the crystalline quality became poor when the growth rate rose above 10 μm/h.