TCAD Analysis of O-Terminated Diamond m-i-p+ Diode Characteristics Dependencies on Surface States CNL and Metal-Induced Gap States

In this article, a 2-D TCAD simulation study on the forward and reverse characteristics of oxygen-terminated diamond (D:O) m-i-p
⁺
Schottky barrier diode (SBD) is carried out considering the effects of Fermi level pinning due to surface states (SSs) and metal-induced gap states (MIGS). The device simulation considers drift-diffusion transport, SS charge neutrality level (CNL), MIGS through Fermi level pinning parameter (
${S}$
), doping and temperature-dependent mobility model, incomplete ionization of dopants, and impact ionization models. The simulation validation is carried out for Al/Au Schottky metals at room temperature and at higher temperatures. A good comparison between the simulation and experiment is obtained around turn-on voltage (
${V}_{T{0}}~\sim ~1.0$
V for Al and ~2.0 V for Au Schottky contacts) and for anode voltage (
${V}_{A}{)} > {V}_{T{0}}$
. Through simulations, we estimated the type of SSs and their quantity, and the position of CNL (
${E}_{\text {CNL}}$
) within the diamond bandgap. The effect of
${E}_{\text {CNL}}$
position and pinning parameter on the forward and reverse characteristics is also simulated. The impact of
${E}_{\text {CNL}}$
and SS on reverse leakage current is also analyzed using a nonlocal barrier tunneling model. At higher temperatures, a good match between simulation and experiment of forward characteristics is achieved.