Single-trap emission kinetics of vertical <i>β</i> -Ga ₂ O ₃ Schottky diodes by deep-level transient spectroscopy

Abstract

Abstract We report the emission kinetics of a single-electron trap (E1, E C –0.63 eV) in Sn-doped ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mn>2</mml:mn> <mml:mo>ˉ</mml:mo> </mml:mover> </mml:math> 01) β -Ga 2 O 3 crystals studied using deeplevel transient spectroscopy (DLTS). The time constant ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>τ</mml:mi> </mml:math> ) of the electrons emitted from the trap level E1 was thoroughly investigated as a function of the temperature and the electric field (E-field) . The temperature-dependence <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow/> <mml:mi>τ</mml:mi> </mml:math> of E1 was extracted by both the temperature-scanning and isothermal modes of DLTS. It was found that the emission process accelerated exponentially from 200 K to 350 K. The E-field dependence of the emission time constant could be divided into two regimes for all measurement steps (250–325 K). In the low-electric-field regime, the emission time constant of the trap decreased slightly with a strengthened E-field. With a further enhancement of the E-field ( E &gt; 1.76 MV cm −1 ), the field-enhanced emission rate was accurately modeled by the Poole–Frenkel effect; the accelerated emission process was attributed to a reduction of the Coulomb well barrier for the donor-like trap E1.