Wurtzite III-nitride distributed Bragg reflectors on Si (100) substrates

TL;DR

This paper reports the first successful growth of wurtzite III-nitride distributed Bragg reflectors on Si (100) substrates, enabling integration of optical devices with silicon technology.

Contribution

It demonstrates the epitaxial growth of crack-free AlN/GaN superlattice DBRs on Si (100) using offcut wafers to control crystal quality.

Findings

Successful growth of 600 nm GaN cap / AlN/GaN DBRs on Si (100)

Use of offcut Si wafers to prevent cubic GaN inclusions

Potential for integrating optical devices with silicon technology

Abstract

Distributed Bragg reflectors (DBRs) composed of an AlN/GaN superlattice were demonstrated for the first time on Si (100) substrates. Single-crystal wurtzite superlattice structures were achieved on this cubic substrate by employing offcut Si (100) wafers with the surface normal pointing 4{\deg} towards the [110] direction. This misorientation introduced an additional epitaxial constraint that prevented the growth of a two-domain GaN surface as well as cubic GaN inclusions. A crack-free 600 nm GaN cap / 5x AlN / GaN DBR structure on Si (100) was demonstrated. This accomplishment of a wurtzite III-nitride DBRs on Si (100) opens the possibility to integrate novel optical and optoelectronic devices with established Si microelectronics technology.