Local atomic structure analysis around Mg atom doped in GaN by X-ray absorption spectroscopy and spectrum simulations

Abstract

The identification of the incorporated site of magnesium (Mg) and hydrogen (H) required for p-type formation in gallium nitride (GaN) power devices has been demonstrated by X-ray absorption spectroscopy (XAS). In this study, the fluorescence line of Mg with 3 × 1019 atoms cm−3 was successfully separated from that of Ga using a superconducting tunnel junction array detector with high sensitivity and high energy resolution, and consequently the Mg K-edge XAS spectra of such dilute samples were obtained. The site of Mg atoms incorporated into the GaN lattice was identified as the Ga substitutional site by comparing the experimental XAS spectrum with the simulated spectra calculated by density functional theory. In addition, the presence or absence of H around Mg can be determined through distinctive characteristics expected from the spectrum simulations.

Distinguishing Sb-containing sites in SnO2 using spectrum simulation of X-ray absorption spectroscopy

“…7) The calculated spectra were consistent with the experimental results. We have studied various semiconductors (N in SiC, Zn in Ga 2 O 3 , and Mg in GaN) using the same method as Mizoguchi et al [8][9][10][11] In this study, the spectrum of substituted Sb at the Sn position was simulated in SnO 2 based on DFT calculations and verified whether it has the same spectrum as that of Sb 2 O 5 . We also simulated the spectra by assuming that the substitution exists in the lattice (i.e., in the interstitial site) due to low temperature during sample preparation.…”

Direct Observation of Atomic Structures and Chemical States of Active and Inactive Dopant Sites in Mg-Doped GaN

“…In the case of p-type GaN, on the other hand, Mg is usually used due to the formation of shallow acceptor levels in the band gap of GaN. For the atomic structures and the chemical states of the Mg-dopant in Mg-doped GaN, various doping sites have been proposed in previous studies. − …”