Effect of surface modification on the radiation stability of diamond ohmic contacts

Abstract

The ohmic contact interface between diamond and metal is essential for the application of diamond detectors. Surface modification can significantly affect the contact performance and eliminate the interface polarization effect. However, the radiation stability of diamond detector is also sensitive to the surface modification. In this work, the influence of surface modification technology on diamond ohmic contact under high-energy radiation was investigated. Before radiation, the specific contact resistivity (ρc ) between Ti/Pt/Au-hydrogen terminated diamond (H-diamond) and Ti/Pt/Au-oxygen terminated diamond (O-diamond) were 2.0 × 10-4 Ω·cm2 and 4.3 × 10-3 Ω·cm2 respectively. After 10 MeV electron radiation, the ρc of Ti/Pt/Au-H-diamond and Ti/Pt/Au-O-diamond were 5.3 × 10-3 Ω·cm2 and 9.1 × 10-3 Ω·cm2 respectively. The change rate of ρc of H-diamond and O-diamond after radiation were 2550% and 112% respectively. The electron radiation promotes the bond reconstruction of diamond surface resulting in the increasing of the ρc .