High performance enhancement-mode AlGaN/GaN MIS-HEMT with selective fluorine treatment

Abstract

A novel enhancement-mode (E-mode) Metal-Insulator-Semiconductor- (MIS-) HEMT with selective fluorine ion (F-) treatment is proposed and its mechanism is investigated. The HEMT features the Selective F- treatment both in the AlGaN channel region and in the thick passivation layer between the gate and drain (SFCP-MIS-HEMT). First, the F- in the passivation layer not only extends the depletion region and thus enhances the average electric field (E -field) between the gate and drain by the assisted depletion effect but also reduces the E -field peak at the gate end, leading to a higher breakdown voltage (BV). Second, in the AlGaN channel region, the F- region realizes the E-mode and the region without F- maintains a high drain current (I D). Third, MIS structure suppresses the gate leakage current, increasing the gate swing voltage and the BV. Compared with a MIS-HEMT with F- treatment in whole channel (FC-MIS-HEMT), SFCP-MIS-HEMT increases the BV by 46% and the saturation drain current (ID,sat) by 28%.