Sub-100 nm Gate Technologies for Si/SiGe-Buried-Channel RF Devices

Abstract

Propagation of sound waves and pulses through a weak inhomogeneous medium with a van der Waals interface is studied in the non-dissipative approximation by using a perturbative technique. It turns out that in some cases the resonance frequency of sound standing waves in a cavity will change from one resonant mode to another according to the detailed shape of the interface. Also, important differences between the standing waves and the pulse techniques are found. These results may provide a promising way to probe weak inhomogeneous interfaces.

Electron effective mobility in strained-Si/Si1−xGex MOS devices using Monte Carlo simulation

“…The biaxial tensile strain introduces splitting of degenerate bands [1] which results, for both electrons and holes, in smaller in-plane conduction mass and reduced intervalley scattering thereby yielding improved carrier velocity. In the case of electrons this effect has been clearly shown from mobility measurement and calculation in SiGe-Si-SiGe quantum wells [2][3][4] and it has been used for designing high-performance MODFET with low noise figure and high cut-off and maximum oscillation frequencies [5][6]. Now efforts are made to transfer this advantage in CMOS technology on either bulk or insulating substrate [7][8][9][10].…”

Optimization of THz response of strained‐Si MODFETs

“…N-channel strained-Si FETs with buried [1] (s-Si MODFET, modulation doped FETs) and surface channels [2] (s-Si MOSFET) were developed. Minimum noise figures as low as 0.4 dB at 2.5 GHz and cut-off frequencies (f T ) in excess of 70 GHz at 300 K were achieved in s-Si MODFET [3].…”

Reduced self-heating in Si/SiGe field-effect transistors on thin virtual substrates prepared by low-energy plasma-enhanced chemical vapor deposition

“…1 Until now, the best device performance has been achieved on graded virtual substrates which are several microns thick. 2 However, a drawback arises from the low thermal conductivity of undoped SiGe which reaches its minimum of ϭ0.08 W cm Ϫ1 K Ϫ1 ) at a Ge concentration of 40%, 3 the optimum value for MODFETs with high sheet carrier density. 4 Several different attempts have been made to realize thin relaxed SiGe buffers ͑see Ref.…”

“…The smallest structures have a gate length of l G ϭ70 nm and a source/drain distance of d SD ϭ1 m. Details of the processes are published elsewhere. 2,10 Room temperature ͑77 K͒ Hall measurements after complete device processing resulted in an electron mobility of 1300 ͑4050͒ cm 2 V Ϫ1 s Ϫ1 at a sheet carrier density of 5ϫ10 12 cm Ϫ2 . This is comparable to typical values for similar structures fabricated on 5-m-thick graded buffers prepared by LEPECVD which show a mobility of 1370 ͑4000͒ cm 2 V Ϫ1 s Ϫ1 and even 10% better than results from 2.5-mthick entirely MBE-grown structures.…”