Study on Self-heating and Drain Voltage Effects for Buffer Traps in GaN HEMTs by Low Frequency S-parameter measurements

Effects of self-heating and drain voltage on buffer traps in GaN HEMTs were investigated by using low frequency S-parameter measurements. Because peaks in Y22 imaginary parts transformed from S parameters is related with the buffer traps, the peak frequency were measured by varying ambient temperatures and drain voltages in low frequency range from 20 Hz to 100 MHz. The experimental results were reproduced well by implementing the self-heating and field enhanced electron emission effects into the Arrhenius equation.