Vacancy-type defects in Al2O3/GaN structure probed by monoenergetic positron beams

Abstract

Defects in the Al 2 O 3 (25 nm)/GaN structure were probed by using monoenergetic positron beams. Al 2 O 3 films were deposited on GaN by atomic layer deposition at 300 C. Temperature treatment above 800 C leads to the introduction of vacancy-type defects in GaN due to outdiffusion of atoms from GaN into Al 2 O 3. The width of the damaged region was determined to be 40-50 nm from the Al 2 O 3 /GaN interface, and some of the vacancies were identified to act as electron trapping centers. In the Al 2 O 3 film before and after annealing treatment at 300-900 C, open spaces with three different sizes were found to coexist. The density of medium-sized open spaces started to decrease above 800 C, which was associated with the interaction between GaN and Al 2 O 3. Effects of the electron trapping/detrapping processes of interface states on the flat band voltage and the defects in GaN were also discussed.

Split Ga vacancies and the unusually strong anisotropy of positron annihilation spectra in β−Ga2O3

“…Positron annihilation spectroscopy is a nondestructive method with selective sensitivity to neutral and negative vacancy-type defects, and second-order sensitivity to negatively charged defects without open volume [11]. Thanks to these properties, positron annihilation methods have been successful in identifying the role of native point defects in the electrical compensation of n-type doped compound semiconductors such as GaN, ZnO, AlN, InN, and In 2 O 3 [12][13][14][15][16], as well as their alloys such as InGaN and AlGaN [17][18][19][20][21][22]. In spite of the otherwise significant research interest in β-Ga 2 O 3 , the number of reported studies with positron annihilation is surprisingly low [23][24][25][26].…”

Annealing Behaviours of Open Spaces in Thin Al2O3 Films Deposited on Semiconductors Studied Using Monoenergetic Positron Beams

“…After the deposition, they were annealed at temperatures ranging (227) up to 900 • C for 3-5 min in N 2 atmosphere. Details on the deposition conditions of the Al 2 O 3 and AlON x films are given elsewhere [5,11,12].…”

Effects of alloy composition and Si-doping on vacancy defect formation in (InxGa1–x)2O3 thin films

“…Measured annihilation parameters are clearly different from the reference values thus indicating presence of defects. An increase in the S parameter typically indicates increase in vacancy-type defect concentration or increase in vacancy volume [140][141][142]. However, the shape of the (S, W) plot for the undoped and highly Si-doped sample ([Si] = 9 × 10 18 cm −3 ) in Fig.…”