Showing papers on "Channel length modulation published in 1971"

Inhomogeneous channel resistivity field effect devices

Abstract: Improvement in the operation of several field-effect devices is predicted through the use of specific longitudinal inhomogeneous channel resistivity profiles with heavier doping near the source than the drain end. One device, an inhomogeneous channel field-effect transistor or ICFET, is shown to have a marked reduction in the product of channel resistance and gate to channel capacitance. Effectively, these results imply that higher frequency operation is possible without reducing the device length. General equations for this device are developed and the cut-off frequency is derived in terms of the distributed resistance and capacitance product. One of the solutions of these equations for an exponential impurity profile has shown that a frequency response improvement of six times and gain bandwidth improvement of thirty times is obtained when the doping level changes by a factor of 100 from source to drain. A homogeneous FET of the same length with the same drain value of doping concentration is used for the comparison, thus keeping the breakdown voltages and pinch-off voltages equivalent. Another device, called the inhomogeneous channel current limiter, is a two terminal field-effect device which has a larger saturation current while the pinch-off voltage and the peak source to drain operating voltage are unchanged. Equations for this device have also been developed and the solutions indicate that the saturation current can be increased by one or two orders of magnitude for a linear impurity profile with a change in doping levels by a factor of 10 or 100 between the source and drain. The comparison is again made with a homogeneous device having a doping concentration equal to that at the drain end of the inhomogeneous device. These results can also be generalized to MOSFET devices.

Characteristics of the junction-gate field effect transistor with short channel length

Abstract: A two-section model of a junction-gate field effect transistor with short channel length was derived. In this model, the current conducting channel is divided into a source and a drain section. The gradual channel approximation with a modification to include the hot electron effect is assumed applicable in the source section. The velocity saturation transport with excess carrier accumulation effect is formulated for the drain section. The normalized design curves and the characteristics of two sample devices are presented.

Modeling and Radiation Effects Study of an LSI/MOS Logic System

Abstract: This paper presents the results of a comprehensive modeling and radiation effects study of a p-channel enhancement mode LSI/MOS test chip (TC) specifically designed to allow measurement of discrete device type parameters and responses for circuits constructed from similar devices on a common chip. Particular emphasis was given to the development of accurate models of the individual devices and to the demonstration of the use of these models in predicting the radiation responses of the circuits on the chip. Ionization dose and neutron effects were determined for each of the parameters used in the model which contained the basic Sah equations modified to include channel length modulation effects, the body effect, and the electric-field-dependence of channel mobility. Average values of these parameters were then used in predictions of pre- and post-radiation responses for circuits.

Experimental study of surface channel in insulated-gate field-effect transistor

Abstract: A simple experimental technique is described for measuring the effective channel length and the surface-channel drift mobility in the insulated-gate field-effect transistor. Experimental results are presented for p channel transistors made in 8 Ω cm silicon.