Low Frequency Noise in Insulated-Gate Strained-Si n-Channel Modulation Doped Field Effect Transistors

摘要

The 1/f noise in insulated gate strained Si n-channel modulation doped field effect transistors (MOSMODFETs) and in control Si metal-oxide-semiconductor FETs (MOSFETs) has been studied at gate voltages below and above the threshold. All transistors have a deposited gate oxide of 20 nm and gate length of 0.5 μm. Mobilities extracted from the capacitance- and current-voltage characteristics were found between 580-700cm~2 V~(-1) s~(-1) for the MOSMODFETs, and between 300-400cm~2 V~(-1) s~(-1) for the Si MOSFETs. In spite of the difference in the mobility both FETs demonstrated identical noise characteristics. The 1/f noise was found well described by the model of number of carriers fluctuations equally below and above threshold. The effective density of traps is ～5 x 10~(10) eV~(-1) cm~(-2) responsible for the noise was within the usual range reported before for regular n-channel Si MOSFETs and somewhat higher than for p-SiGe MODFETs.