AbstiactThis paper presents the d e g m b o n of fT and f-in CMOS devices at elevated temperame. Since MOS transistors in RF applications are usually in d o n region and f7 of CMOS devices is proportional to g , a simple empirical model for temperature dependence of g, at any measurement bias has been suggested by considering the temperature dependence of a canier mobility and a saturation velocity simultaneously. From the empirical temperature behavior of g , we can predict the enhanced RF performances of CMOS at low temperatllre. in d o n region, the temperature dependence offT and f , should be characterized by the combination of the temperahlre dependence of pef and v , , . In this work, the temperature dependence of& and f , in CMOS devices have been measured. Since& and f , are proportional to g, the degradation of& and f , can be explained by a simple empirical model for tempemtm behavior of g, which was taken into considemtion of both canier mobility and d o n velocity degadahon. II . Device Fabrication and Measurement I . Introduction With the scaling towards an extreme sub-micrometer regime, a cut-off tkquency UT) of CMOS as high as 150 GHz and Si MMIC have been reported to replace GaAs MMIC in RF h n t e n d IC's[ 1-31. Generally, high channel tempeiature has well known detrimental effects on the performances of MOS devices such as threshold voltage shift, transconductance d e w o n , and distortion of the Dc I-V charactenstl cs. To explain the transconductance degradabon with the increase of temperature, there have been extensive studies on the temperature dependence of effective canier mobility ( p ) and saturation velocity (v, ), separately [4,5]. When the MOS transistor is operated in the saturation region, the channel region can be divided into two regions such as a strong inversion region and a velocity saturation region. Therefore, the tempemture dependent g behaviors in the saturation region should be described by the temperature dependence of p and v,, simultaneously. Particularly, since MOS transistors in RF applications are usually biased . . eff eliThe CMOS transistors used in this work were &-hid using a 0.8 wn twin-well CMOS process on the p Si with resistivity of 2000 Q an. The gate oxide thickness is 175A, and a TiSi silicide process was used to reduce the sowcedrain parasitic resistance. The gate pattern for RF chamcterization is multi-finger type with common sourcebulk configclration. All the test devices used in this work have 10 fingers with L4.8 rn and unit finger width Wu=lO lla Small signal scattering ( S ) m e t e r s have been measured using on-wafer RF probes of Cascade Microtech and a HP 8510C network analyzer at temperature ranging h m 300 to 473K.On-wafer dummy structures were employed to deembed pad parasites. Measured S parameters were converted into admittance (Y) parameters, and the inbinsic device characteristics were calculated in the Y domain by using a deembedded technology.The cut-off hquency V;) and maximum h u e n c y (&A have been determined as the frequency whe...

Compared with internal combustion engine vehicles and electric vehicles, the advantages of fuel cell vehicles are still in a qualitative stage, and there is no clear quantitative analysis. In this paper, the energy consumption and emission results of twelve different hydrogen paths are calculated through the secondary modeling in GREET, and the total energy consumption and emissions of fuel cell vehicles, internal combustion engine vehicles, and electric vehicles are obtained. The results show that electric vehicles have the lowest energy consumption throughout their life cycle, and fuel cell vehicles are only about 22% higher than electric vehicles. At the same time, based on the analysis of multi-factor environmental indicators such as global warming potential, human toxicity potential, photochemical smog potential, aerosol potential and acidification potential, fuel cell vehicles have the lowest life cycle emissions. Finally, a comparison of the total cost of ownership of the three representative vehicles shows that the cost of fuel cell vehicles is the highest under current production. However, combined with the analysis of the cost reduction space of the main components of the fuel cell system, the results show that when the mileage is higher than 56,000 kilometers, The total cost of ownership of fuel cell vehicles will be lower than internal combustion engine vehicles.

Minimum operating voltages (Vmin) of every cell on a 32kb fully-depleted (FD) SOI static random access memory (SRAM) macro are successfully measured. The competing Vmin distribution models, which include the gamma and log-normal distribution, are approximated using the generalized gamma distribution (GENG). It is found that Vmin of the cells follow the gamma distribution. This finding gives a simple method to estimate worst Vmin of an SRAM macro by measuring few samples and make linear extrapolation from the gamma distribution.