Linear voltage-controlled resistance element
AssigneeThe Trustees of Columbia University
InventorYannis Tsividis
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Abstract
The channel resistance of a MOSFET is made independent of V.sub.S -V.sub.D by maintaining the ends of the gate electrode adjacent the source and drain regions at an offset voltage with respect to the source and drain regions, respectively, and by maintaining the portions of the body region adjacent to the source and drain regions at another offset voltage with respect to the source and drain regions, respectively. In this manner, V.sub.S -V.sub.D appears across the channel, across the gate, and across the body region beneath the channel. The resulting linear voltage drops along each of the three causes the channel-to-gate and channel-to-body potentials to be constant along the entire length of the channel, thereby avoiding variations in the number of carriers, mobility variations and body effect in the channel.
Claims9
A voltage-controlled linear resistance device comprising:
- a field-effect transistor having spaced source and drain regions formed in a semiconductor body region, a first electrode for applying a first voltage signal to the source region, a second electrode for applying a second voltage signal to the drain region, and a gate electrode overlying the body region between the source and drain regions, the gate electrode having a first end adjacent to the source region and a second end adjacent to the drain region;
- first means for applying a first offset voltage between the source region and the first end of the gate electrode, and between the drain region and the second end of the gate electrode;
- and
- second means for applying a second offset voltage between the source region and a portion of the body region adjacent to the source region, and between the drain region and a portion of the body region adjacent to the drain region,
- whereby the resistance between the first and second electrodes is substantially constant with respect to the voltage across the first and second electrodes.
Dependencies are inferred from the claim text.