Modeling of A New MOSFET for ASICS

Abstract

For many years , negative resistance solid state devices are being increasingly used in oscillator circuits 0 In particular , voltage controlled negative resistance devices have been investigated due to the simplicity in circuit design 0 The tunnel diode was known as the only device whose negative resistance comes from the purely internal physical mechanism o Because of the disadvantage of low output voltage swing and the fact that it is a two terminal device , the tunnel dide leads to serious circuit design difficulties 0 In this thesis we present a novel idea of a negative resistance device whose negative resistance comes from the purely internal physical mechanism 0 The new device is based on the floating gate MOSFET ( FG­ MOSFET ) technology 0 This technology allows the new device to be free from the majority of drawbacks of those devices which already exist 0 We called the new device NR-MOSFET , whereas NR stands for negative resistance 0 The NR-MOSFET device incorporates a trapezoidal channel MOSFET which is designed where the channel form is bias dependent , in which the channel width close to drain decreases as the drain voltage Vns increases and I or the gate voltage. Vas decreases 0 This bias dependent channel enables us to realize a voltage controlled negative resistance which is easy to realize by using the standard 5MOSFET technology on chip with other circuitries and develop many original applications 0 _ The construction and theory of operation of the new device is presented 0 Analytical modeling of the new NR-MOSFET device I-V characteristics is derived 0 A two - dimensional analytical model is elaborated to evaluate the ditribution of the longtudinal channel field and potential of the NR-MOSFET and to predict their dependence on the