The influence of electric field and mobility profile on GaAs MESFET characteristics
Abstract
Analytical approximations for the drain I-V relationship, including the mobility profile and field distribution in the channel from the drain to the source, of GaAs MESFETs are derived. The model includes the extended depletion from the gate to the drain for nonself-aligned devices. The calculation of the electric field along the channel is in very good agreement with existing analytical models and a two-dimensional numerical simulation. Experimentally, the authors fabricated and tested tilted angle lightly doped drain (LDD) GaAs MESFETs. It was found that the LLD MESFET structure suppresses the peak electric field under the gate near the drain region. A lower output conductance and higher drain-to-source breakdown were observed as expected. In addition to the electric field, the mobility profile is another factor that influences the performance of the devices. The accuracy of describing the low-field transconductance is strongly dependent on the mobility profile. Moreover, the mobility profile modifies the electric field along the channel and also influences the shape of the drain I-V curves. It is found that more accurate I-V curves can be obtained once the mobility profile is taken into account.
- Publication:
-
IEEE Transactions on Electron Devices
- Pub Date:
- November 1989
- DOI:
- 10.1109/16.43660
- Bibcode:
- 1989ITED...36.2405C
- Keywords:
-
- Carrier Density (Solid State);
- Electron Mobility;
- Field Effect Transistors;
- Gallium Arsenides;
- Schottky Diodes;
- Volt-Ampere Characteristics;
- Debye Length;
- Digital Simulation;
- Jfet;
- Transconductance;
- Electronics and Electrical Engineering