Carrier Trapping in High Electron Mobility Structures
Original Publication Date: 1985-Feb-01
Included in the Prior Art Database: 2005-Feb-18
In high electron density transistors of the field-effect type wherein the channel between the source and drain electrodes is made up of epitaxial thin layers that are alternately doped and essentially undoped, an increased number of carriers can be provided in the essentially undoped layers by constructing an energy condition that tends to retain the electrons in the vicinity of the layer interface. The energy condition, as shown in Fig. 1 for a depletion-mode transistor of GaAs and GaAlAs, is provided by the use of undoped and graded doping. The principle may be applied to permit high transconductance and low trapping, as shown in Fig. 2.