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The direct coupled field-effect transistor logic (DCFL) which
consist of MESFET is widely used for large scale integrated
circuit because of its simple circuit and low power
dissipation. In addition, MESFET is also an important structure
for opto-electrical applications. Unfortunately,the Schottky
barrier height between metal and Ⅲ-Ⅴ material is low owing to
Fermi-level pinning, this results in low logic swing and makes
circuit easily disturbed by noise which limit the work
characteristics of MESFET. Recently, the Schottky barrier
height is improved by depositing an amorphous material layer
which has high energy gap between metal and Ⅲ-Ⅴcompound
semiconductor to bring about slow interface state at interface.
In this thesis, we deposit three different amorphous materials
(a-Si:H, a-SiC:H, a-SiGe:H) between metal (we use Al, Au, Pt)
and Ⅲ-Ⅴ smeiconductor and observe the change of Schottky
barrier height, reverse leakage current, and breakdown voltage.
From experiment,we found that the Schottky barrier height
between Au/SiC(200A) is the highest in GaAs and Pt/Si(80A) in
InP. In these three amorphous materials, SiC has the least
reverse leakage current and the largest breakdown voltage. We
use Au/SiC( 500A) as the gate to fabricate field-effect
transistor and the transconductance(gm) is 1.5 ms/mm.
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