M‐plane III‐nitride materials for polarization sensitive devices grown by PAMBE with real time analysis by spectroscopic ellipsometry

Abstract

In this paper we present a study of the growth of M‐plane GaN epilayers on LiAlO2 substrates under Ga rich conditions and growth at Ga stable conditions by plasma assisted molecular beam epitaxy (PAMBE) coupled with in‐situ spectroscopic ellipsometry (SE). Previous studies on M‐plane materials have suggested that optimum growth conditions with respect to surface morphology are those giving rise to Ga trilayer coverage at low growth temperature. By studying Ga adsorption/desorption in vacuum and in the presence of active nitrogen, we find that the total coverage for M‐plane material is distinctly different for these two conditions. Under vacuum, the stable Ga coverage corresponded of 0.48 nm, while a thicker Ga stable coverage of 0.7 nm was determined N plasma. Using these GaN growth conditions, M‐plane InGaN layers were grown and fabricated into polarization‐sensitive photodetectors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)