Effects of Si passivation on Ge metal-insulator-semiconductor interface properties and inversion-layer hole mobility

The impact of Si passivation (SP) on Ge metal-insulator-semiconductor interface properties and the inversion-layer mobility of Ge p-type metal-insulator-semiconductor field effect transistors (PMISFETs) were investigated by using the devices with different thicknesses of the SP layers. SP was effective in decreasing the total charged centers instead of the interface traps. As a result, the inversion-layer hole mobility of the Ge MISFET was significantly improved by introducing the SP layers of the appropriate thickness. This improvement is attributable to the reduction of the amount of the interface charges and the separation of the positions of mobile carriers and the interface charges by the SP layers.