Raman Scattering Spectroscopy of Residual Stresses in Epitaxial AlN Films

Abstract

High-crystalline-quality epitaxial films of wurtzite AlN were grown by metalorganic vapor phase epitaxy (MOVPE) and hydride vapor phase epitaxy (HVPE). The lattice strain of the films was analyzed by high-resolution X-ray diffraction and the E2 (high)-phonon frequency was observed by Raman scattering. Data analysis for wide ranges of lattice strains and phonon-peak shifts yielded a precise biaxial stress coefficient of this phonon mode, -4.04±0.3 cm-1/GPa. Furthermore, the deformation potential constant was accurately determined from the biaxial stress coefficient.

Structural and optical properties of thick freestanding AlN films prepared by hydride vapor phase epitaxy

“…The 657.5 cm À 1 frequency value of the E 2 2 phonon, which is conveniently used for film stress measurements, acquired near the center of the film (at the front and back surface, represented in Figs. 3a and b) is very close to the value of 657.4 cm À 1 determined for zero-stress film [14,15]. Therefore, within the experimental error of the published results and of our measurements, it could be stated that the central part of the film is stress free.…”

Alteration of structural and optical properties in quaternary Al0.1In0.1Ga0.8N films using ultraviolet assisted photo-electrochemical etching route

“…8) calculated from XRD and photoluminescence (PL), respectively for the porous films. The acquired K R values of porous AlInGaN films were within the range reported for GaN (4.2) [76], InN (9.0) [77], and AlN (4.0) [78]. It could be deduced from Fig.…”

Effect of the growth temperature on the properties of AlxGal−xN epilayers grown by HVPE

“…E 2 (high) peak positions of the Al x Ga 1 À x N epilayer were 566.25, 568.03 and 570.74 cm À 1 . The E 2 (high) peak position of GaN is 567.6 cm À 1 [13] and that of AlN is 657.4 cm À 1 [14]. The peak positions of Al x Ga 1 À x N epilayer lie between that of GaN and AlN [15].…”