Yoshihiro Hara

A novel high performance SiGe channel heterostructure dynamic threshold pMOSFET (HDTMOS)

In this letter, we propose a novel SiGe channel heterostructure dynamic threshold metal oxide semiconductor (DTMOS) and demonstrate its superiority over conventional Si-DTMOS. The introduction of a SiGe layer for the channel is very effective for reducing the threshold voltage in spite of keeping impurity doping level at the body region. Therefore, a low threshold voltage and a large body effect factor can be achieved simultaneously. The SiGe HDTMOS with highly doped body exhibits two times higher transconductance, 1.4 times higher saturation current, and better short channel immunity than that of the control Si-DTMOS with lightly doped body of which threshold voltage is nearly the same.

Low-frequency noise characteristics in SiGe channel heterostructure dynamic threshold pMOSFET (HDTMOS)

We present the first investigation of low frequency noise in the SiGe channel heterostructure dynamic threshold p-MOSFET (HDTMOS). The sub-threshold characteristics and drain current noise were measured and evaluated. The input referred noise of the SiGe HDTMOS was reduced to about one-tenth compared with that of the Si MOS, because of higher transconductance g/sub m/ and less interface states at the Si/SiGe hetero-interface.

A novel low-voltage N-channel heterostructure dynamic threshold voltage MOSFET (N-HDTMOS) with p-type doped SiGe body

A novel N-channel Si/SiGe heterostructure dynamic threshold voltage MOSFET (N-HDTMOS) has been proposed and fabricated. The Si/SiGe N-HDTMOS consists of an unstrained surface Si channel and heavily p-type doped SiGe body. The potential of the conduction band edge of the surface Si channel can be lowered by introducing a heavily p-type doped SiGe layer into a suitable position in the body region. As a result, the N-HDTMOS shows a threshold voltage reduction and a body effect factor (/spl gamma/) enhancement while keeping high doping concentration in the SiGe layer. The fabricated SiGe N-HDTMOS exhibits superior properties, that is, 0.1 V reduction of V/sub th/, 1.5 times enhancement of /spl gamma/, and 1.3 times saturated current, as compared with those of Si N-DTMOS.