Analysis of the current-transport mechanism across a CVD diamond/silicon interface

This work presents a study on the mechanism of injection and charge transport through a CVD diamond/n+-Si interface. The current-voltage-temperature characteristics of CVD diamond/silicon heterojunctions measured in the temperature range 119-400 K have been interpreted according to thermionic theory and thermionic field-emission theory. This junction shows deviations from the ideal thermionic theory current model, suggesting the presence of surface states, thin-layer depletion and/or non-homogeneity in the diamond/silicon interface. The T0 anomaly has been used to explain the behaviour of the ideality factor with temperature. At very low temperatures tunnelling may occur because the E00 values for these junctions are close to the value expected by thermionic field-emission theory. The usual activation-energy plot deviates from linearity at low temperatures. This deviation has been corrected supposing a ln(JS/T2) versus 103/nT plot. Under these conditions the Richardson constant is found to be 0.819 A cm−2 K−2, which is close to the theoretical value of 1.2 A cm−2 K−2. Field-emission device is a promising application for diamond/silicon structure.