High resistivity halide vapor phase homoepitaxial β-Ga2O3 films co-doped by silicon and nitrogen

Abstract

Semi-insulating halide vapor phase epitaxial β-Ga2O3 films without intentional dopants introduced during growth are demonstrated. The sheet resistance measured in the 340–480 K range yielded 268–134 kΩ/◻ and an activation energy of 0.81 eV. Room temperature capacitance-voltage measurements at 1 MHz showed evidence of an ultra-low free carrier concentration n-type film with a free carrier concentration near flatband (VFB ∼ 4.4 V) estimated to be <1014 cm−3, resulting in a high breakdown voltage of 2380 V (3.18 MV/cm) measured on a lateral diode without field termination. Secondary ion mass spectroscopy did not reveal Fe compensating species; however, an average Si concentration of about 5 × 1015 cm−3 and an N concentration of about 2 × 1017 cm−3 were detected, suggesting that N acceptors compensated Si donors to result in a nearly intrinsic β-Ga2O3 film. Photoionization spectroscopy suggested the presence of a deep acceptor-like level located at Ec −0.23 eV.

Deep-Level Traps Responsible for Persistent Photocurrent in Pulsed-Laser-Deposited β-Ga2O3 Thin Films

“…Either native interstitial, or Si substitution at the octahedral Ga site, was proposed as the origin of this donor level. Tadjer et al reported a trap located 0.23 eV below the conduction band in halide vapor phase epitaxial β-Ga 2 O 3 which was co-doped by Si and N impurities [19]. The effect of twin boundaries that induced structural disorder on the electronic properties of homoepitaxial β-Ga 2 O 3 thin films was Crystals 2021, 11, 1046 2 of 8 also studied.…”

Photovoltaic and flexible deep ultraviolet wavelength detector based on novel β-Ga2O3/muscovite heteroepitaxy

“…The possible origin of this trap is still unknown. Tadjer et al reported a trap located 0.23 eV below conduction band in halide vapor phase epitaxial Ga 2 O 3 which was co-doped by Si and N impurities 51 . Therefore, the E 2 trap of 234 meV may be originated from unintentional nitrogen doping.…”

Damage Recovery and Dopant Diffusion in Si and Sn Ion Implanted β-Ga2O3

“…48 Insulating Ga 2 O 3 with lower densities of compensating acceptors, such as the recently reported Si/N compensated material, could be used as well. 16 However, such Ga 2 O 3 material has not been demonstrated to-date.…”

“…The β-polymorph of Ga 2 O 3 is of interest for power electronics and solar blind UV detectors due its wide bandgap (∼4.85 eV) and high critical field (6-8 MV/cm). The availability of high-quality large area and low cost wafers, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] especially those grown by the edgedefined film-fed growth (EFG) method 6 in combination with these attractive properties have potentially positioned β-Ga 2 O 3 to supplement the more established wide bandgap semiconductors, SiC and GaN, in compact, high power density converters for power switching applications. 3,4,7,8,11,12 In addition to the progress in bulk growth, there is now the capability to grow high quality epilayers with controlled net free-electron concentrations in the range 10 15 -10 19 cm −3 using shallow Si, Ge, and Sn donors.…”