β-Ga₂O₃ defect study by steady-state capacitance spectroscopy

Abstract

We use steady-state capacitance measurement originally intended for capacitance–voltage experiment to observe and characterize the electrical properties of deep defects in β-Ga2O3 semiconductors. We detect a deep level located 0.81 eV below the conduction band edge with a concentration of 1.2 × 1016 cm−3 and a capture cross-section of 1.1 × 10−14 cm2, making it potentially influential in determining the performance of β-Ga2O3 based power electronic and optoelectronic devices. This deep level may dominate the thermal activation of off-state drain current in β-Ga2O3 transistors at high temperatures and, together with another shallower level at 0.13 eV, may substantially lower the breakdown voltage in Schottky diodes.

Investigation on temperature dependent DC characteristics of gallium oxide metal-oxide-semiconductor field-effect transistors from 25 °C to 300 °C

“…The obtained E A is different from the other group's report of ∼0.8 eV 24) and the source of these traps is unclear.…”

Ti- and Fe-related charge transition levels in β−Ga2O3

“…Some discrepancies in reported donor ionization energies might be related to the dependence of the donor ionization energy on the charge carrier concentration [100,129,130]. Several deeper donor levels have been reported in the range between 90 meV to 210 meV [107,126,[131][132][133]. Such donor levels would only be partially-ionized at room temperature, and hence could affect the operation of β-Ga 2 O 3 -based devices [107].…”

Suppression of persistent photoconductivity in high gain Ga2O3 Schottky photodetectors*

“…Accord-ing to literature reports, the concentration of oxygen vacancies in Ga 2 O 3 is generally 10 16 -10 18 cm −3 . [12][13][14][15] If we assume that the concentration of oxygen vacancies in our Ga 2 O 3 film is about 10 17 cm −3 , the donor concentration in Ga 2 O 3 is about 10 17 cm −3 under ultraviolet light. Therefore, it can be understood that the donor concentration increases under light, which will cause the image force and tunneling effect to become stronger, so the effective Schottky barrier height is reduced more, and the carriers are more likely to pass through the Schottky junction.…”

“…Recently, Ga 2 O 3 and related materials have attracted widespread attention due to their potential applications in optoelectronic and microelectronic devices. [1][2][3][4][5][6][7][8][9] Although significant progress has been made in the research of Ga 2 O 3 based devices, the manipulation and understanding of its defects and related physical characteristics still demand further research, [10][11][12][13][14][15][16][17][18] for example, the defect-related photoconductivity gain and persistent photoconductivity (PPC) observed in Ga 2 O 3 photodetectors. [19][20][21][22][23][24][25] The photoconductive gain increases the responsivity of the device, which is conducive to the detection of weak light, while PPC increases the response recovery time of the device, which is not conducive to the detection of high-frequency switching light.…”