David I. Shahin 1, Kiran Kumar Kovi2, Aayush Thapa1, Yizhou Lu1, Ilya Ponomarev2, James E. Butler2, and Aris Christou1
1CALCE, Center for Advanced Life Cycle Engineering, Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20740, USA
2Euclid TechLabs, Gaithersburg, MD 20879, USA
Abstract:
Field effect transistors (FETs) have been fabricated on
smooth (< 3 Å RMS roughness) hydrogen-terminated
diamond substrates. FETs with a 25 nm thick Al2O3
dielectric exhibited slightly normally-off behavior with
threshold voltage of -0.8 V and maximum output current
of 36.8 mA/mm at -10V drain bias. Open air storage and
testing of the devices resulted in no shifts in the transfer
characteristics, although a slight degradation in output
current was observed. The degradation in drain current
is believed to be due to passivation of the hydrogen
termination by atmospheric contaminants penetrating
the Al2O3 dielectric layer.