Analysis of GaN Damage Induced by Cl₂/SiCl₄/Ar Plasma

Abstract

We examined the effect of radiation damage and annealing on the optical properties of nitrogen-gettered nearly IIa type synthetic diamonds. It was found that the 2.156 eV centre, whose absorption is usually very weak, appears in these diamonds as one of the dominant absorption features. A new vacancy-related vibronic absorption system with zero-phonon line at 3.420 eV was observed. A pronounced photochromic effect was established for the 1.945, 2.085, 2.156, 3.420 and 4.325 eV absorption bands. Of all these bands only the 2.156 eV band remains in the absorption spectra after a proper photoexcitation. In contrast, for similarly treated type Ib diamonds we did not reveal any photoinduced changes in the 1.945 eV band absorption. Based on the results of optical bleaching and thermal recovery experiments, we conclude that the assignment of the 2.156 eV centre to the neutral charge state of the nitrogen-vacancy defect needs further verification. § Corresponding author.

Nanoscale GaN Epilayer Grown by Atomic Layer Annealing and Epitaxy at Low Temperature

“…The ALA treatment leads to significant enhancement of crystallinity of AlN thin films . However, the Ar plasma treatment at a high plasma power might cause undesired deterioration, such as crystal damage, of the deposited films. , As a result, it is necessary to reduce the plasma power or use other plasma species in the ALA treatment for the materials with relatively weak bonding strength. It has been reported that the damage caused by the He plasma is less than that by the Ar plasma due to the smaller mass and momentum of He ions .…”

Effects of Cl2-Based Inductively Coupled Plasma Etching of AlGaN on Interface Properties of Al2O3/AlGaN/GaN Heterostructures

“…During ICP etching using the Cl 2 / BCl gas mixture, active Cl à and Cl 3 species react with the AlGaN surfaces to form volatile products, such as GaCl 3 and AlCl 3 . 19,20) These dominants reaction and the subsequent formation of N 2 result in the successful etching of the AlGaN surface. However, there can be additional chemical reactions.…”

Damage characteristics of n-GaN thin film surfaces etched by ultraviolet light-assisted helium plasmas

“…Since the peak wavelength of the UV light emitted from the black light lamp is 365 nm (3.4 eV), the photon flux of the emitted UV light at the surface is estimated to be 6 × 10 18 m −2 s −1 . The penetration depth of the UV light in GaN is known to be a few hundred nm [20]. As described above, a spectrum of UV light emitted only from the He plasma showed a peak at a wavelength of 388 nm at each gas pressure [19].…”