Impact ionization phenomena in AlGaAs/GaAs HEMTs

The impact ionization current in AlGaAs/GaAs high-electron-mobility-transistors (HEMTs) is evaluated by means of measurements of the gate current and high drain voltages. A previously reported method to calculate impact ionization coefficient in GaAs MESFETs is extended to HEMTs. Results agree with the hypothesis that impact ionization takes place nearly exclusively in GaAs, and closely follow previously reported data for the electron impact ionization coefficient in [110] GaAs.<
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