Direct measurements of trap density in a SiGe/Si hetero-interface and correlation between the trap density and low-frequency noise in SiGe-channel pMOSFETs

The interface trap density in a SiGe/Si heterostructure has been successfully measured for the first time using a low-temperature charge pumping technique in a SiGe-channel pMOSFET, avoiding interference from the interface traps between the gate oxide and the semiconductor surface. Moreover, low-frequency noise in the SiGe pMOSFETs has been measured to investigate any correlation with the trap density observed at the SiGe/Si hetero-interface. A good correlation was obtained between the measured interface trap density in the heterostructure and the low-frequency noise level in the current flowing in the SiGe-channel.