Wurtzite III–Nitride Distributed Bragg Reflectors on Si(100) Substrates

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° 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.

Growth, morphology, and structural properties of group‐III‐nitride nanocolumns and nanodisks

“…However, in this material system, a large number of periods and/or a high Al content will lead to cracking of the DBR and, consequently, of the whole device structure, due to the large lattice and thermal mismatches involved. Cracks have often been avoided by a careful use of straincompensating AlN and (Al,Ga)N/AlN superlattices in order to reduce the accumulated strain [49,50]. These approaches are not always efficient and would increase the complexity of the so fabricated devices.…”

Nature of luminescence and strain in gallium nitride nanowires

“…It is known that the crystal structure of the substrate can affect the quality and orientation of the semiconductor nanowire; however, this effect can be decoupled [4]. Still, a diameter-dependent transition must exist where a nanowire experiences the lateral stresses universal to growth in oxide openings or mesas [5] as well as continuous thin films [6].…”

Inductively coupled plasma etching of nano-patterned sapphire for flip-chip GaN light emitting diode applications

“…The critical escape angle is limited by the large differences in refractive index (n) of semiconductors (n GaN = 2.5) and sapphire (n sapphire = 1.78) with air (n air = 1) [7][8][9][10]. Focused-ion beam and masked lithographic etching of photonic crystal structures, KOH-based wet etching for surface roughening, and etching of anodized aluminum oxide have been used to increase the light extraction efficiency [9][10][11][12][13]. However, these techniques are not applicable to large wafers and remain difficult to control, particularly for the lack of selectivity in KOH-based wet etching.…”