The conventional

${p}$

-GaN in Schottky-type

${p}$

-GaN gate HEMTs is converted into an insulator-like

${p}$

-GaN, i.e., fully depleted

${p}$

-GaN in the reverse-biased Schottky junction under forward gate bias (

${V}_{\text {GS}}$

), by inadequate activation of Mg. Consequently, the gate current (

${I}_{\text {G}}$

) is reduced by 3–5 orders of magnitude at

${V}_{\text {GS}}$

of 7-V over a temperature range of 25 °C–150 °C, compared with devices adopting conventional adequate activation. The fully depleted

${p}$

-GaN converts the current-balance-based forward

${V}_{\text {GS}}$

division in the conventional partially depleted

${p}$

-GaN gate stack, into thickness-based voltage division in

${p}$

-GaN and AlGaN between gate and channel, which is like that in a MIS (metal-insulator-semiconductor) gate. As a result, the hole current through the Schottky junction is significantly reduced while the electron spillover current starts to dominate at high forward

${V}_{\text {GS}}$

. Besides, hot carriers are excluded from the forward gate breakdown mechanism.

Marco Silvestri

Publications