David Shahin1, Yizhou Lu1, Aayush Thapa1, Alex Yuan1, Matt Yung1, Kiran Kovi2, James e. Butler2, and A. Christou1
1CALCE, Center for Advanced Life Cycle Engineering, Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20740, USA
2Euclid Techlabs, Cleveland, Ohio, 44139, USA
Abstract:
Diamond transistors with surface 2D conduction channels are projected to be radiation hard with respect
to neutrons. However, ionizing radiation hardness may be a problem due to the disruption of the 2D hole
concentration. In this paper, the processing of three terminal devices with 2D surface conducting
channels is presented as well as analysis of device transfer characteristics. This paper addresses the
fabrication, gamma radiation induced defects and device characteristics of field effect transistors (FET)
built on 1) high quality diamond surfaces exploiting the 2 dimensional surface conductivity, and 2) the
surface two dimensional “hydrogen terminated” conduction layer in diamond single crystals grown by
CVD. In particular, the fundamental physics of radiation effects on two dimensional conduction layers in
diamond materials is an unexplored area which could lead to new breakthroughs in the performance of
high power microwave transistors in extreme environments such as high temperature and high radiation
fields. Gamma radiation is shown to be effective in achieving a 2X increase in drain current as well as an
increase in drain to source saturation current and transconductance. The results are compared to GaN
enhancement mode FETS which show a significant degradation of transconductance.