A Low Program Voltage Enabled Flash like AlGaN/GaN Stack Layered MIS-HEMTs Using Trap Assisted Technique

In this paper, a flash like Al2O3/SiO2 stacked layer AlGaN/GaN-based metal insulator semiconductor high electron mobility transistor (MIS-HEMT) was fabricated using trap assisted technique. The MIS-HEMT showed a large positive shifting of threshold voltage ( increment V-TH) of 4.6 V after applying a low program voltage (V-P) of 3 V, resulting in a very low threshold voltage of -0.3 V with a decent maximum drain current (I-DMAX) of 575 mA mm(-1). A ultraviolet-ozone (UV/O-3) surface treatment was done prior to gate dielectric deposition to produce a thin gallium oxynitride (GaOXNY) layer at GaN/oxide interface, which correspondingly acts as a charge trapping layer, resulting in the reduction in V-P. The capacitance-voltage (C-V) measurements revealed that the traps contributing to the significant positive shifting of V-TH had a density of 5.7 x 10(12) cm(-2). These traps were attributed to the border or oxide defects. A significant reduction in gate leakage current (I-G) of more than three orders of magnitude was found in MIS-HEMT, due to the high quality Al2O3/SiO2 stack gate dielectric layer compared to conventional HEMT. The flash like stack layered programmed MIS-HEMT exhibited a G(MMAX) of 123 mS mm(-1), on-off ratio of 1.7 x 10(7), subthreshold slope of 121 mV dec(-1) with a reduced gate leakage current of 7.5 x 10(-9) A mm(-1).

Automated summary

A flash-like Al2O3/SiO2 stacked layer AlGaN/GaN-based MIS-HEMT was fabricated using trap assisted technique, showing a significant positive shifting of threshold voltage after applying low program voltage. The device exhibited a low threshold voltage and decent maximum drain current, along with a reduction in gate leakage current.