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Title: High-temperature stable W/GaAs interface and application to metal--semiconductor field-effect transistors and digital circuits

Journal Article · · J. Vac. Sci. Technol., B; (United States)
DOI:https://doi.org/10.1116/1.583652· OSTI ID:5979135

The thermal stability of the physical, chemical, and electrical properties of W thin films sputter deposited on GaAs were investigated. A variety of characterization methods, including thin film stress analysis, Auger analysis, Rutherford backscattering spectrometry (RBS) analysis, and Schottky barrier measurements showed that the W/GaAs interface remains stable after high-temperature furnace annealing at 900 /sup 0/C for 15 min or rapid-lamp annealing at 1000 /sup 0/C for 11 s. Some refractory metal compounds were also investigated, including, WSi, WN/sub x/, and TaSi/sub x/. Pure W films produced the best Schottky diode characteristics. The average Schottky barrier height was 0.70 +- 0.009 V across a 2-in wafer after furnace annealing at 800 /sup 0/C/15 min. Pure W self-aligned gate (SAG) metal-semiconductor field-effect transistors (MESFET) and digital circuits were also fabricated. Transconductances as high as 300 mS/mm (L/sub g/ = 1.0 ..mu..m) were measured for enhancement mode SAG MESFET's. Circuits were fabricated with SAG MESFET enhancement-resistor mode logic using pure W gates, including ring oscillators, with gate delay as low as 25 ps and divide-by-eight circuits that functioned at a frequency >1 GHz.

Research Organization:
Hughes Research Laboratories, Malibu, California 90265
OSTI ID:
5979135
Journal Information:
J. Vac. Sci. Technol., B; (United States), Vol. 5:6
Country of Publication:
United States
Language:
English