A1GaN/GaN HEMTs Grown by Molecular Beam Epitaxy on Sapphire, SiC, and HVPE GaN Templates
Abstract
Molecular Beam Epitaxy of GaN and related alloys is becoming a rival to the more established Metalorganic Vapor Phase Epitaxy. Excellent control of impurity, interface abruptness, and in- situ monitoring of the growth are driving the increase in quality of MBE epilayers. We have developed nucleation schemes with plasma-assisted MBE on three types of substrates, consisting of sapphire, semi-insulating (SI-) SiC, and HVPE SI-GaN templates on sapphire. While sapphire and SI-SiC are established substrates for the growth of AlGaN/GaN HEMT epilayers, HVPE GaN templates may provide a path to low-cost large-diameter substrates for electronic devices. We compare device results of HEMTs fabricated on these substrates. As a metric for device performance, the saturated RF power output in class A operation is measured at 2 GHz. We achieved a saturated power density of 2.2 W/mm from HEMTs on sapphire, 1.1 W/mm from HEMTs on HVPE GaN templates on sapphire, and 6.3 W/mm from HEMTs on semi-insulating 611-SiC substrates. The difference in output power can be attributed to self-heating due to insufficient thermal conductivity of the sapphire substrate, and to trapping in the compensation- doped HVPE template.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2002
- Accession Number
- ADP015080
Entities
People
- J. W. Hsu
- K. Baldwin
- L. N. Pfeiffer
- M. J. Manfra
- Nils G. Weimann