TWO-DIMENSIONAL NUMERICAL SIMULATION OF HEMT AND THE EFFECT OF FAST NEUTRONS ON ITS PERFORMANCE
NEVINE AMIN MAHMOUD;
Abstract
Heterostructure devices have proven to be superior to other semiconductor devices such as MESFETs, JFETs and MOSFETs. High Electron Mobility Transistor (HEM1) is the most familiar type of these heterostructure devices. It provides high mobility, high electron velocity and low noise figure. It has achieved a switching speed of 5.8 ps at 77 K, a noise figure of 0.8 db at room temperature and a cutoff frequency of about 200 GHz.
In this thesis, a two-dimensional numerical simulator (for the HEM1)
which uses the finite difference method is presented. It is written in C-language and runs on a personal computer. The simulator solves the Poisson's and continuity equations iteratively at each mesh point of the device. It calculates the potential and carrier concentration at each point. The results of simulator for various AlGaAs/GaAs HEMT devices (with gate lengths between 0.3 and 1J.lffi, AlGaAs thickness : 25 - 80 run, spacer layer thickness : 0-9 run, AlGaAs doping :
5x1017 - 5x10'' cm-3) are presented. The results include the potential and the carrier distribution all over the device with special attention at the heterojunction, the sheet carrier concentration , the drain DC I/V characteristics and the transconductance. The results showed that the AlGaAs thickness and doping concentration should be adjusted to provide maximum confinement of the carriers in the channel to achieve best performance of the device.
Because of the high speed and low noise figure of HEMT, it can be used in military as well as space applications where it may be exposed to different types of radiation. Since the HEMT is relatively a new device, insufficient data is published for the effect of radiation on it. In this work, the simulator is used to study the effect of neutron irradiation on the HEMT. The effects studied are those due to displacement damage since ionization effects caused by gamma rays proved to be less important on HEMTs. The effect of neutron irradiation
In this thesis, a two-dimensional numerical simulator (for the HEM1)
which uses the finite difference method is presented. It is written in C-language and runs on a personal computer. The simulator solves the Poisson's and continuity equations iteratively at each mesh point of the device. It calculates the potential and carrier concentration at each point. The results of simulator for various AlGaAs/GaAs HEMT devices (with gate lengths between 0.3 and 1J.lffi, AlGaAs thickness : 25 - 80 run, spacer layer thickness : 0-9 run, AlGaAs doping :
5x1017 - 5x10'' cm-3) are presented. The results include the potential and the carrier distribution all over the device with special attention at the heterojunction, the sheet carrier concentration , the drain DC I/V characteristics and the transconductance. The results showed that the AlGaAs thickness and doping concentration should be adjusted to provide maximum confinement of the carriers in the channel to achieve best performance of the device.
Because of the high speed and low noise figure of HEMT, it can be used in military as well as space applications where it may be exposed to different types of radiation. Since the HEMT is relatively a new device, insufficient data is published for the effect of radiation on it. In this work, the simulator is used to study the effect of neutron irradiation on the HEMT. The effects studied are those due to displacement damage since ionization effects caused by gamma rays proved to be less important on HEMTs. The effect of neutron irradiation
Other data
| Title | TWO-DIMENSIONAL NUMERICAL SIMULATION OF HEMT AND THE EFFECT OF FAST NEUTRONS ON ITS PERFORMANCE | Other Titles | محاكاة رقمية لنبائط ال HEMT وتأثير النيوترونات المعجلة على أدائه | Authors | NEVINE AMIN MAHMOUD | Issue Date | 1998 |
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