The low temperature (100 °C) deposition of Sc2O3 or MgO layers is found to significantly increase the output power of AlGaN/GaN HEMTs. At 4 GHz, there was a better than 3 dB increase in output power of 0.5 × 100 μm2 HEMTs for both types of oxide passivation layers. Both Sc2O3 and MgO produced larger output power increases at 4 GHz than conventional plasma-enhanced chemical vapor deposited (PECVD) SiNx passivation which typically showed ≤ dB increase on the same types of devices. The HEMT gain also in general remained linear over a wider input power range with the Sc2O3 or MgO passivation. These films appear promising for reducing the effects of surface states on the dc and rf performance of AlGaN/GaN HEMTs.
Bibliographical noteFunding Information:
Manuscript received May 13, 2002; revised July 1, 2002. This work was supported in part by Office of Naval Research under Contract N00014-98-1-02-04 and National Science Foundation under Contracts DMR0101438 and CTS 9901173. The review of this letter was arranged by Editor D. Ritter.
- Surface states
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering