GaN/AlGaN Devices for Space-Based Defense Systems.
Abstract
Report developed under SBIR contract for topic BMDO99-005. The objective of this effort was to design and develop GaN MODFETs with minimal semiconductor volume to minimize radiation damage, particularly due to neutron radiation. High-quality GaN and AlN films were grown on Si and sapphire; MODFETs were fabricated on sapphire which exhibited a transconductance of approx. 150 mS/mm. We succeeded in selectively removing Si substrates using an HNO3:HF solution; methods to remove sapphire substrates using laser ablation were investigated. After obtaining the GaN films, we developed a scheme for mounting nitride films on a high thermal conductivity substrate such as AlN. Electron-radiation studies with Schottky-barrier diodes fabricated on GaN layers were carried out and a baseline for defects established. MODFETs were also subjected to electron radiation. In an effort to develop efficient methods for etching, we used GaN samples in a 13.56-MHz RF parallel-plate reactor with well-characterized electrical parameters. Gas mixtures used were HBr/Ar, CH3Br/Ar, and HBr/He. The optimum etch rate achieved was 73 nm/min using a 30% HBr/70% He gas mixture at 80-W RF power and at 150-mTorr pressure. The effort described lays the groundwork for manufacturing radiation-resistant transistors for commercial and military space applications.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 27, 2000
- Accession Number
- ADA373822
Entities
People
- Hadis Morkoç
- Peter Bletzinger