Epitaxy Part A. LEDs Based on Heteroepitaxial GaN on Si Substrates

Abstract

Recently, LEDs based on heteroepitaxial GaN on Si substrates (GaN/Si) are attracting a great attention and are industrially developed by many companies in order to compete with LEDs based on GaN/sappire and GaN/SiC which are commercially marketed advancing GaN/Si LEDs, though GaN/Si LEDs have been realized early in 2002. The recent attention on GaN/Si is due to the availability of low cost and large wafer size availability (up to 300 mm diameter) of Si substrates. In this article, we review the developments of the GaN epitaxial growth on Si and summarize the developments made in our laboratory including the device structures achieving the GaN/Si LEDs with higher emission efficiency. We describe on GaN/Si using (i) high temperature (HT) AlN/AlGaN intermediate layers, (ii) HT intermediate layers (ILs) and multilayers (MLs), and (iii) strained-layer superlattices (SLS) interlayers and their LED performances respectively. We believe that GaN/Si LEDs with low prices will become important LEDs for general lighting in the near future.