Delay time analysis of submicron InP-based HEMT's

Abstract

The intrinsic delay time of submicron InP-based HEMT's has been evaluated by coupling the delay time analysis with a 2D Ensemble Monte Carlo Simulation. The relationship between the delay time and the transit time is explained. It is shown that the delay time can be quite different from the transit time depending on the velocity modulation. The delay from each segment of the HEMT is calculated to study the distribution of the delay inside the device. The delay from the gate region was the major contributor while that from the drain region was also important. The bias dependence of the delay in each region of the device was calculated to explain the bias dependence of the total intrinsic delay time. The intrinsic delay time increase at low V/sub gs/ was due to the increase of /spl tau//sub d/ and /spl tau//sub s/ and the increase at high V/sub ds/ was due to the increase of /spl tau/d. As a means of validation, the simulated data have been compared with experimental intrinsic delay time data at various bias points. Good agreement was found over a wide V/sub gs/ and V/sub ds/ range.