Defect characterization in metal-oxide-semiconductor field-effect-transistors with trench gates by electron beam-induced current technique

The electron beam-induced current and scanning deep level transient spectroscopy methods are applied to metal-oxide-semiconductor field-effect-transistors with trench gates in order to investigate the defects in the oxide layer and silicon bulk. A dark spot corresponding to an oxide defect is observed in the EBIC image when the current is measured at the gate terminal with the source terminal grounded. By varying the accerelation voltage, we estimate that the defect exists in the oxide of side wall in the trench at 2.2 mu m from the surface. A pinhole of 0.2 mu m in diameter is observed in the oxide at the exact position by focused-ion beam technique.