GaN heteroepitaxial growth on silicon nitride buffer layers formed on Si (111) surfaces by plasma-assisted molecular beam epitaxy

Abstract

Wurtzite GaN films were grown on silicon nitride buffer layers formed on Si (111) substrates by radio frequency plasma-assisted molecular beam epitaxy. Reflection high energy electron diffraction, Auger electron spectroscopy, transmission electron microscopy, and photoluminescence results indicate that the single crystalline wurtzite GaN was grown on the buffer layers of amorphouslike silicon nitride formed on Si (111) substrates by taking the following relationship with the substrate: GaN [0001]//Si [111] and GaN (1̄1̄20)//Si (11̄0). Both faces of the silicon nitride buffer layer were found to be flat and sharp, the thickness of the buffer layer (1–1.5 nm) being constant across the interface. Efficient bound exciton emission was observed at 3.46 eV. The growth technique described was found to be simple but very powerful for growing high quality GaN films on Si substrates.

The influence of nitridation time on the structural properties of GaN grown on Si (111) substrate

“…11(b)) for sample F it is observed that this thin layer is amorphous SiN x (a-SiN x ). This a-SiN x is also observed in several Si/AlN systems [33,34,[36][37][38][39][40][41][42].…”

“…According to some others, there exists in the SiN x a top layer of a few atomic distances that is crystalline [36]. According to Dobos et al [37], Nakada et al [36], and Kaiser et al [34], the epitaxial relationship is transferred from Si into AlN and GaN through the amorphous SiN x layer by the presence of crystalline regions, Si 3 N 4 inclusions, or holes in the SiN x layer. Other explanations include the short-range tetrahedral coordination that was maintained in the SiN x layer [34,41,42], and the nucleation and growth of GaN islands from intrinsic or extrinsic defects by a "pinhole model" [40].…”

“…One reason could be the short-range tetrahedral coordination of each atom, which is obviously continued in the SiN x layer. Another explanation could be small crystalline SiN or Si 3 N 4 within the interlayer, which transfer the orientation relation [34,36]. Secondly, a locally, thicker SiN x layer in the structures can cause the interrup- (Fig.…”

“…One of the suggestions was that the amorphous SiN x layer has some short range order that necessitates the orientation of the AlN layer in this fashion [34]. According to some others, there exists in the SiN x a top layer of a few atomic distances that is crystalline [36]. According to Dobos et al [37], Nakada et al [36], and Kaiser et al [34], the epitaxial relationship is transferred from Si into AlN and GaN through the amorphous SiN x layer by the presence of crystalline regions, Si 3 N 4 inclusions, or holes in the SiN x layer.…”

“…If the interface was truly between the AlN and Si substrate, the crystallographic relationship and relatively high dislocation density, originating from the interface due to the large lattice mismatch between the two crystals, would provide a straightforward explanation. However, the AlN/Si interface has been shown, in the present study and others, to contain an amorphous SiN x layer [34,36,37]. The orientation relationships were determined for GaN-AlN on Si (111) by taking the selected area electron diffraction (SAED) patterns in TEM (Fig.…”