NASA SBIR 02-1 Solicitation


PROPOSAL NUMBER:02- E2.04-8267 (For NASA Use Only - Chron: 023732 )
SUBTOPIC TITLE: Advanced Communication Technologies for Near-Earth Missions
PROPOSAL TITLE: High-Frequency, Low-Noise Nitride-Based Power Transistors Grown on Bulk III-N

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
SVT Associates, Inc.
7620 Executive Drive
Eden Prairie , MN   55344 - 3677
(952 ) 934 - 2100

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Amir Dabiran
7620 Executive Drive
Eden Prairie , MN   55344 - 3677
(952 ) 934 - 2100

One of the main issues for III-nitride growth is the lack of a suitable native substrate. Growth on foreign substrates such as sapphire or SiC results in nitride material with a high density of defects due to large mismatches in lattice constant and thermal expansion. Nonetheless, nitride devices grown on these substrates have demonstrated optical and electronic properties that are practically unmatched by other material systems. In particular, the AlGaN/GaN high electron mobility transistors (HEMTs) constitute a leading candidate for simultaneously realizing ultrahigh-frequency low-noise amplifiers and power amplifiers. Here, we propose to use high quality bulk GaN and AlN substrates for substantial improvements in the operation of AlGaN/GaN HEMTs. We also propose a method of isolating the n-type substrate from the active layer. In this way, we take advantage of the reduced thermal and lattice mismatch, lower density of treading dislocations, and improved thermal conductance to significantly improve the dc and RF operation of these devices. Some projected HEMT device parameters to achieve are a current density > 1.5A/mm, extrinsic transconductance values > 400 mS/mm, fmax > 200 GHz, and power density > 10 W/mm at 40 GHz.

The AlGaN-based high electron mobility (HEMT) power transistors have wide commercial markets in radar and range finding, collision avoidance, digital transmission (including HDTV, MMDS and LMDS), satellites, and automobiles and engine sensors. The high temperature and high single-transistor power capabilities would make the devices particularly useful for portable and aerospace applications. A successful Phase I effort will result in substantially improved nitride HEMTs on bulk AlN and GaN substrates with record dc and microwave properties.

The electron transport properties at the AlGaN/GaN interface along with the high electron saturation velocity and high breakdown fields in GaN are the basis for the superior performance of nitride-based high electron mobility transistors (HEMT). These devices show high-frequency low-noise and high-power operation. Furthermore, the nitride devices are radiation hard and can operate at elevated temperatures. Applications such as satellite communication would greatly benefit from the improved performance of III-N HEMTs grown on native substrates.

Form Printed on 09-05-02 10:10