Modulation Doped GaAs/Al sub xGA sub (1-x)As Layered Structures with Applications to Field Effect Transistors.
Abstract
We have established a device fabrication laboratory, dc and rf device testing facilities and materials characterization facilities. Initially, a great deal of effort was spent to improve the molecular beam epitaxial growth of heterojunctions. Later-on the dependence of heterojunction properties on the structural parameters were investigated in detail and in the process, separation of donor and electrons by about 200 A in a modulation doped structure was discovered to lead to extremely high electron mobilities. Transport parallel to the heterointerface in normal and inverted structures was investigated at moderate fields for the first time. Polar optical phonon emission above 200 V/cm field strengths was found to be responsible for mobility reduction. High field transport properties was deduced from the FET performance. Modulation doped field effect transistors with a micron gate length and a 3 micron channel length were fabricated and characterized under dc operating conditions at both 300 and 77 K. A model was also developed to analyze the device operation and performance. Using this model, the heterojunction structures were optimized for high performance field effect transistors. In a different area, a scheme which replaces the Schottky barrier of a MESFET with a n(+)/p(+) structures grown in situ with the channel layer was developed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 15, 1982
- Accession Number
- ADA126392
Entities
People
- Hadis Morkoç
Organizations
- University of Illinois Urbana–Champaign