The analysis of double doping polysilicon gate Lightly-doped-drain (LDD) MOSFET

A new type of field effect transistor (FET), the double doping polysilicon gate (DDPG) Lightly-doped-drain (LDD) MOSFET, is proposed and demonstrated. The gate of the DDPG LDD MOSFET adopts gate engineering. This novel gate structure takes advantage of material work function. The arrangement is such that the gate near the source is comprised of P-type polysilicon and the gate near the drain is N-type polysilicon. The model is simulated with a 2-D device simulator MEDICI over wide range of device parameters and bias conditions and we get curves such as electric field, surface potential, threshold voltage and driving current. The simulation result shows that an appropriate threshold voltage can be gotten by changing the doping concentration of polysilicon. Meanwhile, the driving capacity is greatly improved compared with the conventional MOSFET. The process of the structure is not complicated which can be easily achieved today.