Correlation of Selected Problems During Gan Movpe Epitaxy on si Substrates with in–Situ Interferometer Observation

Abstract

In this paper, selected problems occurring during GaN epitaxy on Si substrates are correlated with in-situ interferometer observations based on structures fabricated using 3×2” Thomas Swan Close Coupled Showerhead MOVPE system. Samples were epitaxially grown on highly resistive (> 500cm) p-type 2” silicon substrates. The growth was observed using an interferometer acquiring reflectance traces in-situ. To avoid issues that are shown in this paper, different approaches of the so-called buffer layer were used by depositing them on Si before the growth of GaN. Different material qualities of grown GaN layers were obtained by variation in films constituting the buffer layer grown before the desirable GaN film. The study shows the evolution of the grown samples, improvement of various parameters and also gradual reduction of material issues discussed in this paper. Improvement in GaN layer was mainly observed by SEM characterization and studying the growth mechanisms through observation of reflectance traces obtained in-situ.

Origin of surface defects and influence of an in situ deposited SiN nanomask on the properties of strained AlGaN/GaN heterostructures grown on Si(111) using metal–organic vapour phase epitaxy

“…The 3D growth mode state and its transition to the 2D growth mode was observed as damping of the in situ reflectance signal, which is a direct measure of roughness. 31,32 The reflectance signal presented in Fig. 1 is an average of reflectance signals probed from evenly distributed points in a line of ∼2 mm, along the grown structure.…”