Effects of recess depths on performance of AlGaN/GaN power MIS-HEMTs on the Si substrates and threshold voltage model of different recess depths for the using HfO2 gate insulator
Abstract
Three types of E-mode AlGaN/GaN MIS-HEMTs with different barrier depths and conventional HEMT were fabricated on the Si substrates. HfO2 gate insulator with a thickness of 30 nm was grown by plasma enhanced atomic layer deposited (PEALD). Characteristics of the four devices with different recess depths are analyzed. The MIS-HEMT with barrier layer thickness of 3 nm features good comprehensive performance. The threshold voltage (Vth) is 1.8 V, the drain current density is 480 mA/mm and the figure of merit (FOM) is 363 MW/cm2. When the barrier thickness is 0 nm, the Vth is up to 3.7 V. A calculation model of threshold voltage for recessed MIS-HEMTs is proposed. When the barrier layer thickness is 6 nm, the calculated value of Vth was 0.3 V which is in good match with the experimental value of 0.4 V. The proposed model provides guidelines for the AlGaN/GaN MIS-HEMTs designs.
- Publication:
-
Solid State Electronics
- Pub Date:
- January 2020
- DOI:
- 10.1016/j.sse.2019.107649
- Bibcode:
- 2020SSEle.16307649Z
- Keywords:
-
- AlGaN/GaN;
- MIS-HEMT;
- HfO<SUB>2</SUB>;
- Breakdown voltage;
- FOM;
- Threshold voltage model