Early predictions that diamond would be a suitable material for high-perfor
mance high-power devices were not supported by the characteristics of diode
s and field effect transistors (FETs) fabricated on boron doped (p-type) th
in-film material. In this paper commercially accessible polycrystalline thi
n-film diamond has been turned p-type by the incorporation of near-surface
hydrogen, a type of film often referred to as 'surface conducting'. Schottk
y diodes and metal-semiconductor FETs (MESFETs) have been fabricated using
this approach which display unprecedented performance levels; diodes with a
rectification ratio>10(6), leakage currents<1 nA, no indication of reverse
-bias breakdown at 100 V and an ideality factor of 1.1 have been made. Simp
le MESFET structures that are capable of withstanding V-DS values of 100 V
with low leakage and current saturation (pinch-off) characteristics have al
so been fabricated. Predictions based upon experiments performed on these d
evices suggest that optimised device structures will be capable of operatio
n at power levels up to 20 W mm(-1) implying that thin-film diamond may aft
er all be an interesting material for power applications. (C) 1999 Elsevier
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