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

Abstract

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 mm. Mobilities extracted from the capacitance-and current-voltage characteristics were found between 580 -700 cm 2 V À1 s À1 for the MOSMODFETs, and between 300 -400 cm 2 V À1 s À1 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 Â 10 10 eV À1 cm À2 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.

1/f Noise and trap density in n-channel strained-Si/SiGe modulation doped field effect transistors

“…Ge% N t (E fn ) (cm À3 eV À1 ) N t (E fn ) (cm À3 eV À1 ) N t (E fn ) (cm À3 eV À1 ) s-Si Schottky-gated MODFET on thick VS (this work) s-Si Schottky-gated MODFET on thin VS (this work) Other work on s-Si MOSFETs (except [5] …”

“…In Ref. [5] a MOS-gated Si/SiGe MODFET with deposited oxides was investigated. The noise in these devices is mainly determined by the oxide-semiconductor interface quality.…”

Sub‐100 nm gate‐length SiGe/Si MIS‐HFET using Cat‐CVD SiN

“…Recently, the incorporation of SiGe heteroepitaxy in Si device structures has been actively studied to advance the present Si metal-oxide-semiconductor (MOS) technology in ways other than the aggressive downscaling of device dimensions. Compared with surface channel devices like MOSFETs, buried channel devices like HFETs or HEMTs show promise for low power consumption, low noise, and high frequency application, although it is more difficult to fabricate these devices [1]. SiGe/Si HFETs are expected to be a key device for ultra-high speed wireless applications on Si platforms such as millimeter wave telecommunications or photonic network systems combined with Si photonics technology.…”