TABLE OF CONTENTS MOS transistor characteristics are strongly temperature dependent. Modeling the temperature dependence of the MOSFET characteristics is important in designing VLSI circuits since, in general, an IC is specified to be functional in a certain temperature range, for example - 55 C to 125 C. In addition, operating the MOSFET below room temperature (lowtemperature operation) results in improved device performance; a factor of two improvement in switching speed can be achieved by operating a 1 ?m device at 77 K (- 196 C) [122] [124]. However, device degradation due to hot-carrier effects also increases with decreasing temperature (see section 8.6) [124].
The MOSFET drain current varies considerably with temperature. The change in drain current in the temperature range 0 100 C for a typical n-channel device is over 20%, being slightly lower for the corresponding p-channel device. The temperature coefficient of the drain current can be positive, negative, or zero depending upon the operating voltages. This is shown in Figure 6.36 where measured 
in saturation is plotted against gate voltage for different temperatures for a nMOST with W m/ L m = 9.4/9.4 ( ?m), t ox = 105 , and V th = 0.56 V. The Zero Temperature Coefficient (ZTC) of the drain current could be either in the linear or saturation region of device operation. The gate voltage, which leads to ZTC is very close to the device threshold voltage, as we shall see...
