Simulation of a Novel Schottky Body-Contacted Structure Suppressing Floating Body Effect in Partially-Depleted SOI nMOSFET's

A novel Schottky body-contacted structure for partially depleted SOI nMOSFET's is presented.This structure can be realized by forming a shallow n +-p junction and two sidewall spacers in the source region,and then growing a thick silicide film,which can punch through the shallow junction and make a Schottky contact to the p-type silicon.Simulation results show that the anomalous subthreshold slope and kink effects are suppressed successfully and the drain breakdown voltage is improved considerably.This method has the same device area and is completely compatible with the bulk MOSFET process.

Influence of body contact of SOI MOSFETs on the thermal conductance of devices

The thermal conductance of devices with different body contacts is studied. A new analytical expression is proposed. This expression can be used in parameter extraction, which gives both good efficiency and high precision. The ratio of thermal conductance of the body contact region to that of the body region is nearly equal to the ratio of the area. The use of an H shape gate body contact is suggested to aid power dissipation in SOI MOSFETs.

A Continuous and Analytical Surface Potential Model for SOI LDMOS

A continuous and analytical surface potential model for SOI LDMOS, which accounts for automatic transitions between fully and partially-depleted statuses,is presented. The surface potential equation of the SOI de- vice is solved by using the PSP′s accurate algorithm of surface potential,and the front and back surface potentials are obtained analytically as a function of gate and drain voltage. The formulations of inversion charge and body charge under the fully-depleted state have been modified. The continuous and analytical DC model for SOl LD- MOS is given based on PSP. The comparisons between simulation and measurements indicate that this model can predict the DC characteristics of SOI LDMOS accurately.

Effects of back gate bias on radio-frequency performance in partially depleted silicon-on-inslator nMOSFETs

The effects of back gate bias(BGEs) on radio-frequency(RF) performances in PD SOI n MOSFETs are presented in this paper. Floating body(FB) device, T-gate body-contact(TB) device, and tunnel diode body-contact(TDBC) device, of which the supply voltages are all 1.2 V, are compared under different back gate biases by different figures of merit, such as cut-off frequency( fT), maximum frequency of oscillation( fmax), etc. Because of the lack of a back gate conducting channel, the drain conductance(gd) of TDBC transistor shows a smaller degradation than those of the others, and the trans-conductance(gm) of TDBC is almost independent of back gate bias. The values of fT of TDBC are also kept nearly constant under different back gate biases. However, RF performances of FB and TB each show a significant degradation when the back gate bias is larger than ～ 20 V. The results indicate that TDBC structures could effectively improve the back gate bias in RF performance.

Eliminating the floating-body effects in a novel CMOS-compatible thin-SOI LDMOS

A novel CMOS-compatible thin film SOI LDMOS with a novel body contact structure is proposed. It has a Si window and a P-body extended to the substrate through the Si window, thus, the P-body touches the P＋ region to form the body contact. Compared with the conventional floating body SOI LDMOS （FB SOI LDMOS） structure, the new structure increases the off-state BV by 54%, decreases the specific on resistance by 20%, improves the output characteristics significantly, and suppresses the self-heating effect. Furthermore, the advantages of the low leakage current and low output capacitance of SOI devices do not degrade.

Nonstationary plane contact problem in theory of elasticity for conformal cylindrical surfaces

A numerical–analytical approach is described to investigate the process of impact interaction between a long smooth rigid body and the surface of a circular cylindrical cavity in elastic space. A non-stationary mixed initial boundary value problem is formulated with a priori unknown boundaries moving with variable velocity. The problem is solved using the methods of the theory of integral transforms, expansion of desired variables into a Fourier series, and the quadrature method to reduce the problem to solving a system of linear algebraic equations at each time step. Some concrete numerical computations are presented.The cylindrical body mass and radius impact on the proile of the transient process of contact interaction has been analysed.