Overdrive voltage

About: Overdrive voltage is a research topic. Over the lifetime, 4427 publications have been published within this topic receiving 53791 citations.

A simple theory to predict the threshold voltage of short-channel IGFET's

Abstract: A simple expression for the threshold voltage of an IGFET is derived from a charge conservation principle which geometrically takes into account two-dimensional edge effects. The expression is derived for zero drain voltage and is valid for short and long-channel lengths. The dependence of the threshold voltage on the source and drain diffusion depth, r j , and channel length, L , is explicitly given. In the limit, L / r j → ∞, the threshold voltage equation reduces to the familiar expression for the long-channel case. The theory is compared with the measured threshold voltages on IGFET's fabricated with 1·4, 3·8 and 7·4 μm channel lengths. The dependence of the threshold voltage under backgate bias voltages ranging from zero to breakdown agrees closely with the theory.

Critical Voltage for Electrical Degradation of GaN High-Electron Mobility Transistors

Abstract: We have found that there is a critical drain-to-gate voltage beyond which GaN high-electron mobility transistors start to degrade in electrical-stress experiments. The critical voltage depends on the detailed voltage biasing of the device during electrical stress. It is higher in the OFF state and high-power state than at VDS = 0. In addition, as |VGS| increases, the critical voltage decreases. We have also found that the stress current does not affect the critical voltage although soft degradation at low voltages takes place at high stress currents. All of our findings are consistent with a degradation mechanism based on crystallographic-defect formation due to the inverse piezoelectric effect. Hot-electron-based mechanisms seem to be in contradiction with our experimental results.

Active matrix type display apparatus and drive circuit thereof

Abstract: Each of picture elements comprises an input transistor for accepting a signal current from a data line when a scanning line is selected, a conversion transistor for converting the signal current into a voltage and for holding thus converted voltage, and a drive transistor for driving a light emitting device with drive current corresponding to the converted voltage. The conversion transistor flows the signal current to its channel to generate the voltage corresponding to the converted voltage and a capacitor to restrain the generated voltage. Further the drive transistor flows the drive current corresponding to the voltage stored in the capacitor. In this case the threshold voltage of the drive transistor is set not to be smaller than the threshold voltage of the conversion transistor, and thereby a leakage current flowing through the light emitting device is suppressed.