Interplay of vacancies, hydrogen, and electrical compensation in irradiated and annealed n-type β-Ga2O3

Abstract

Positron annihilation spectroscopy, Fourier transform-infrared absorption spectroscopy, and secondary ion mass spectrometry have been used to study the behavior of gallium vacancy-related defects and hydrogen in deuterium (D) implanted and subsequently annealed β -Ga 2 O 3 single crystals. The data suggest the implantation generates a plethora of V Ga -related species, including V Ga1 -and V Ga2 -type defects. The latter's contribution to the positron signal was enhanced after an anneal at 300 • C, which is driven by the passivation of V ib Ga by hydrogen as seen from infrared measurements. Subsequent annealing near 600 • C returns the positron signal to levels similar to those in the as-received samples, which suggests split V Ga -like defects are still present in the sample. The almost complete removal of the V ib Ga -2D vibrational line, the appearance of new weak O-D lines in the same spectral region, and the lack of D out-diffusion from the samples suggest that the 600 • C anneal promotes the formation of either D-containing, IR-inactive complexes or defect complexes between V ib Ga -2D and other implantation-induced defects. The degree of electrical compensation is found to be governed by the interactions between the Ga vacancies and hydrogen.

Diversity of split Ga vacancies in β-Ga2O3

“…The data are shown for semi-insulating Mg and Fe doped crystals, n-type Sn doped and unintentionally doped (uid) crystals, a Si-doped (n-type) thin film and an ion-irradiated Fe doped crystal. [23][24][25] In addition to the experimental data, the figure shows with scale bars the overall anisotropy of positron annihilation signals obtained from theoretical calculations for the β-Ga2O3 lattice and two types of Ga vacancy defects. 23 To highlight the unusual magnitude of the anisotropy of these signals, the overall anisotropy measured in GaN and ZnO is shown for reference.…”

“…[11][12][13][14][15][16][17][18][19][20] The differences in the positron annihilation signals caused by these complexes are subtle but observable, in particular when more than two defects participate in the complex. [23][24][25]…”

“…In β-Ga2O3 relative changes of the S parameter as high as 4% have been measured by rotating the samples. [23][24][25] The root cause appears to lie in the quasi-one-dimensional positron state in the β-Ga2O3 lattice, 23 but the detailed mechanisms are not yet known. Luckily, this phenomenon allows for making interpretations on defect identities based on the nature of the anisotropy when the two general conditions of defect identification fail.…”

“…Based on the experimental data, it is highly likely that these in-grown split Ga vacancies are present in the form of different types of complexes with O vacancies and hydrogen, in addition to the different configurations of the isolated split Ga vacancies. [23][24][25]…”

Liquid Ga–In–Sn Alloy Printing of GaInSnO Ultrathin Semiconductor Films and Controllable Performance Field Effect Transistors

“…The defects including oxygen vacancy and gallium vacancy etc. will be formed with the growth of Ga 2 O 3 , resulting in a low carrier concentration and n-type conductivity of natively grown Ga 2 O 3 . − For power electronic devices based on Ga 2 O 3 , the high carrier concentration and carrier mobility are essential. Doping provides a promising way to enhance the conductivity of native Ga 2 O 3 .…”