Showing papers on "NQS published in 2001"

A compact non-quasi-static extension of a charge-based MOS model

Abstract: This paper presents a new and simple compact model for the intrinsic metal oxide semiconductor (MOS) transistor, which accurately takes into account the non quasistatic (NQS) effects. This is done without any additional assumption or simplification than those required in the derivation of the classical description of the MOS channel charge. Moreover, the model is valid from weak to strong inversion and nonsaturation to saturation. The theoretical results are in very good agreement with measured data performed on devices of various channel length, from 300 /spl mu/m down to 0.5 /spl mu/m, and in various modes of operation.

Frequency-dependent resistive and capacitive components in RF MOSFETs

Abstract: It is found from measured high frequency (HF) S-parameter data that the extracted effective gate sheet resistance (R/sub gsh/), effective gate unit-area capacitance (C/sub gg, unit/), and transconductance (G/sub m/) in radio-frequency (RF) MOSFETs show strong frequency dependency when the device operates at frequencies higher than some critical frequency. As frequency increases, R/sub gsh/ increases but C/sub gg, unit/ and G/sub m/ decrease. This behavior is different from what we have observed at low or medium frequencies, at which these components are constant over a frequency range. This phenomenon has been observed in MOSFETs with L/sub f/ longer than 0.35 /spl mu/m at frequencies higher than 1 GHz, and becomes more serious as L/sub f/ becomes longer and the frequency higher. This behavior can be explained by a MOSFET model considering the Non-Quasi-Static (NQS) effect. Simulation results show that an RF model based on BSIM3v3 with the NQS effect describes well the behaviors of both real and imaginary parts of Y/sub 21/ of the device with strong NQS effect even though its fitting to Y/sub 11/ needs to be improved further.

Ouput buffer circuit

Abstract: An output buffer circuit is provided, which is capable of obtaining a large drive power when the level of an input signal changes, while allowing a through current to flow in suppressed amounts. A first P-channel MOS transistor and a first N-channel MOS transistor are connected in series with a power supply. The pair of transistors are exclusively switched on and off by an input signal such that the first and second switching elements are not simultaneously on or off, to deliver an output signal corresponding to the input signal, from a common junction between the first and second switching elements. A second P-channel MOS transistor is connected in parallel with the first P-channel MOS transistor as an auxiliary transistor. A second N-channel MOS transistor is connected in parallel with the first N-channel MOS transistor as an auxiliary transistor. When the level of the input signal changes to switch one of the first P-channel MOS transistor and N-channel MOS transistor from an OFF state to an ON state, a drive switching control block delivers a signal to one of the auxiliary transistors connected in parallel with the switched one of the first P-channel MOS transistor and N-channel MOS transistor, for holding the one of the auxiliary transistors in an ON state over a predetermined time period.

When do we need non-quasistatic CMOS RF-models?

Abstract: This paper presents criteria for the onset of NQS effects derived from time transient device simulations and S-parameter measurements. For the first time it has been proved that e.g, a 10 /spl mu/m NMOS transistor can be described up to 27 MHz and a 0.2 /spl mu/m device up to 46 GHz by the quasistatic approach while the accuracy of the description of the inversion layer charge is still 99%.

An Efficient Frequency-Domain Analysis Technique of MOSFET Operation

Abstract: We propose a harmonic balance technique for the frequency-domain analysis of MOSFET operation. Our approach is based on the charge-sheet and the non-quasistatic(NQS) MOSFET models in the channel region with the harmonic balance(HB) technique applied to the channel charges. Lateral field effect is considered in the formulation to analyze the short channel MOSFET devices. It is shown that the proposed method renders a computationally efficient tool to analyze the harmonic distortion occurrence in the MOSFET devices due to the nonlinear response of the channel charges.