Experimental Investigation on Threshold Voltage Instability for β-Ga2O3 MOSFET Under Electrical and Thermal Stress

A
$\beta $
-Ga
₂
O
₃
MOSFET is fabricated and its threshold voltage
$({V}_{\mathrm{TH}})$
instability mechanisms are experimentally investigated under different gate-biased voltages and ambient temperatures. Under the condition of the positive bias stress (PBS) of
${V}_{\mathrm{GS}} = 4$
V for 1000 s at room temperature, the
${V}_{\mathrm{TH}}$
positive shift of 0.61 V is mainly caused by the electrons trapped by border traps in Al
₂
O
₃
. Combining the hysteresis with temperature-dependent performance analysis, the clockwise to anticlockwise hysteresis inversion at 125 °C is discovered in
$\beta $
-Ga
₂
O
₃
MOSFET for the first time, which is probably caused by the activation of deep-level acceptor-type interface states. The deep-level acceptor-type interface states with a fitting activation energy of 114 meV are found, and they also affect the
${V}_{\mathrm{TH}}$
instability at high temperature. With the stress of
${V}_{\mathrm{GS}} =4$
V at 125 °C for 1000 s,
${V}_{\mathrm{TH}}$
is increased by 0.9 V. Analyzing electrical parameters, such as
${V}_{\mathrm{TH}}$
, subthreshold slope (
SS
), and hysteresis width, can distinguish the quantitative contributions of interface states and border traps to
${V}_{\mathrm{TH}}$
instability under electrical stress and thermal stress (TS). This work reveals an important indication for investigating the
${V}_{\mathrm{TH}}$
instability of
$\beta $
-Ga
₂
O
₃
MOSFET in high-power applications.