H. Tranduc

A new lateral power MOSFET for smart power ICs : the LUDMOS concept

In this paper, a new concept of lateral DMOSFET for medium voltage (<100 V) smart power integrated circuits is proposed. These structures present a trench in the drift region filled with oxide or with oxide and polysilicon. These structures called LUDMOSFET feature a reduced specific on-resistance and enhanced breakdown voltage. For example, for a breakdown voltage of 50 V, the specific on-resistance is 1.2 mΩ cm 2 in the conventional LDMOSFET, 0.8 mΩ cm 2 in the LUDMOS without polysilicon (i.e. 30 percent reduction) and 0.6 mΩ cm 2 in the LUDMOS with polysilicon (i.e. 50 percent reduction). They are technologically compatible with advanced CMOS processes using trench isolation.

Improvement of the ON resistance of power VDMOS devices by surface doping: effect on the breakdown voltage☆

Abstract An efficient way to improve the ON resistance Ron of a vertical double-diffused MOS device is to implant a shallow, lightly doped layer over the drift area of the device. The evolution of Ron for different voltage handling capacities vs. (i) the junction depth and (ii) the concentration of this layer was studied. The figure of merit (the product of Ron and the surface area) of the device was calculated using an analytical unidimensional model and with a two-dimensional numerical simulator. The influence of this surface doping technique on the breakdown voltage of the device was investigated. Comparison between the analytical and numerical approaches shows that two-dimensional effects are important. The trade-off between the factor of merit and the breakdown voltage is emphasized and design rules to use the surface doping technique for devices with voltage handling capacities of 50, 150 and 400 V are given.

Power MOS devices : Structure evolutions and modelling approaches

In this survey paper, the historical evolution of power MOS transistor structures is presented and mostly used actual devices are described. General considerations on current and voltage capabilities are discussed and configuration of popular structures is given. It then presents a synthesis of different modelling approaches proposed in recent years. These include analytical solutions for basic electrical parameters, e.g. threshold voltage, on resistance, saturation and quasi-saturation effects, temperature impact and voltage handling capability. The numerical solutions of basic semiconductor devices are then briefly described along with some typical problems which can be solved this way. The compact circuit modelling method is finally explained with emphasis on dynamic behaviour modelling. Physical-numerical models are detailed together with those intended for circuit simulation. A fairly exhaustive bibliography is given for completeness.

Performance in R.F. power MOSFET's amplifier for GSM radiotelephony

With advantages like good power gain, high input impedance and thermal stability, power MOSFETs working in the GSM radiotelephony UHF channel become more and more serious challengers of bipolar transistors in power amplification domain. Our paper aims to present a model that allows general circuit simulators to deal as well with the study of this kind of devices as with the design of RF power amplifiers or power electronics circuits.