Interface quality of SOI MOSFET´s reflected in noise and mobility

The trap density of both front and back interfaces of SOI (silicon-on-insulator) devices is estimated using low frequency noise measurement. The authors present the complete set of effective mobilities for both n- and p-channel SOI MOSFETs at both the front and back channels and relate them to the trap densities. It is found that the interface qualities of the front and back sides are similar in SIMOX (separation by implanted oxygen) SOI MOSFETs from the noise and mobility standpoint. The very low field effective mobility of SOI NMOS is lower than that of bulk NMOS due to increased interface trap densities for SOI devices and the effective mobility of the edge transistor is lower