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Investigation of Recessed Gate AlGaN/GaN MIS-HEMTs with Double AlGaN Barrier Designs toward an Enhancement-Mode Characteristic
- Source :
- Micromachines, Vol 11, Iss 2, p 163 (2020)
- Publication Year :
- 2020
- Publisher :
- MDPI AG, 2020.
-
Abstract
- In this work, recessed gate AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) with double AlGaN barrier designs are fabricated and investigated. Two different recessed depths are designed, leading to a 5 nm and a 3 nm remaining bottom AlGaN barrier under the gate region, and two different Al% (15% and 20%) in the bottom AlGaN barriers are designed. First of all, a double hump trans-conductance (gm)−gate voltage (VG) characteristic is observed in a recessed gate AlGaN/GaN MIS-HEMT with a 5 nm remaining bottom Al0.2Ga0.8N barrier under the gate region. Secondly, a physical model is proposed to explain this double channel characteristic by means of a formation of a top channel below the gate dielectric under a positive VG. Finally, the impacts of Al% content (15% and 20%) in the bottom AlGaN barrier and 5 nm/3 nm remaining bottom AlGaN barriers under the gate region are studied in detail, indicating that lowering Al% content in the bottom can increase the threshold voltage (VTH) toward an enhancement-mode characteristic.
Details
- Language :
- English
- ISSN :
- 2072666X
- Volume :
- 11
- Issue :
- 2
- Database :
- Directory of Open Access Journals
- Journal :
- Micromachines
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.7441520be1d44604b80decf3542eb975
- Document Type :
- article
- Full Text :
- https://doi.org/10.3390/mi11020163