Investigation of a Self-Aligned, Strained-Channel, N+ -InAs/Al sub 0.5 Ga sub 0.5 AS/In sub 0.15 Ga sub 0.85 AS Semiconductor Insulator Semiconductor FET (SISFET)
Abstract
The idea of a new type of Semiconductor Insulator Semiconductor Field Effect Transistor (SISFET) device has been investigated. The attempted design consists of a heavily doped n-type InAs gate with undoped Al(0.5)Ga(0.5)AS as the gate insulator and with undoped In(0.15)Ga(0.85)As as a strained-channel on an undoped GaAs buffer layer. SISFETs provide freedom from the Donor compleX (DX) center and have threshold voltages which are independent of the AlGaAs doping and thickness. Calculations predict that the proposed pseudomorphic structure would produce a device with a natural threshold voltage of approximately 0.6 volts. This would be well suited to digital logic applications. Calculations also predict that this new material structure would provide a barrier to gate leakage of greater than 0.3 volts up to 2.5 volts of positive gate bias. The layers were grown by MBE, and devices were fabricated using a self-aligned process which involved ion implantation and rapid thermal annealing. Some finished samples exhibited transistor action, but problems included inordinately high gate leakage and non-ohmic source and drain contacts. Theses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 1988
- Accession Number
- ADA203147
Entities
People
- David W. Rapp
Organizations
- Air Force Institute of Technology