Investigation of reactively sputtered tungsten nitride as high temperature stable Schottky contacts to GaAs

Journal Article · Sat Nov 01 00:00:00 EST 1986 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.573634· OSTI ID:7241033

Geissberger, A E; Sadler, R A; Leyenaar, F A; Balzan, M L

Tungsten nitride (WN/sub x/) was deposited onto 2-in.-GaAs substrates by reactively sputtering a tungsten target in a N/sub 2//Ar plasma. The films were deposited at a power density of 5.4 W/cm/sup 2/ and total pressure of 1.33 Pa (10 mTorr). The partial pressure of N in Ar was varied from 0 to 0.5. Auger analysis of the WN/sub x/ films indicated the nitrogen content varied between 0 and 20 at. %. The films were also found to contain between 0.5 and 2 at. % of oxygen. Resistivity measurements of the as-deposited films indicate a linear relationship between film resistivity and atomic percent of nitrogen in the film. Stress measurements were erratic and showed no correlation with atomic percent of N in the film. The average interfacial stress was 2.4 GPa, with a standard deviation of 0.9 GPa. Schottky contacts were patterned on ion-implanted 2-in.-GaAs wafers by reactive ion etching (RIE) the WN/sub x/ film in a CF/sub 4//O/sub 2/ plasma. The diodes were then capped with chemical vapor deposited (CVD) SiO/sub 2/ and annealed at temperatures up to 850 /sup 0/C. The temperature stability of WN/sub x/ films is maximized at 4 at. % of nitrogen, and the postanneal (810 /sup 0/C for 20 min) ideality factor (n) and barrier height (phi/sub B/) for WN/sub 0.04/ films are excellent: n = 1.18, sigma/sub n/ = 0.008, phi/sub B/ = 0.727 eV, and sigma/sub phi//sub B/ = 0.005 eV. State-of-the-art self-aligned gate field-effect transistors (FET's) were fabricated using WN/sub 0.04/ as the gate metallization.

• Research Organization: ITT-Gallium Arsenide Technology Center, Roanoke, Virginia 24019
• OSTI ID: 7241033
• Journal Information: J. Vac. Sci. Technol., A; (United States), Vol. 4:6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GALLIUM ARSENIDES
VAPOR DEPOSITED COATINGS
SCHOTTKY BARRIER DIODES
FABRICATION
TUNGSTEN NITRIDES
ELECTRIC CONDUCTIVITY
STRESSES
VACUUM COATING
ANNEALING
INTERFACES
POTENTIALS
SPUTTERING
ARSENIC COMPOUNDS
ARSENIDES
COATINGS
DEPOSITION
ELECTRICAL PROPERTIES
GALLIUM COMPOUNDS
HEAT TREATMENTS
NITRIDES
NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
REFRACTORY METAL COMPOUNDS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SURFACE COATING
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360203 - Ceramics
Cermets
& Refractories- Mechanical Properties
360204 - Ceramics
Cermets
& Refractories- Physical Properties