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Henderson, Timothy Scott 2014-12-15T19:05:40Z 2014-12-15T19:05:40Z 10000-01-01 1988 1988 Described in this thesis are the growth and characterization of (In,Ga)As/(Al,Ga)As modulation-doped field-effect transistors (MODFETs). The use of a thin strained layer of (In,Ga)As for the current-carrying channel takes advantage of the superior transport properties of this material while maintaining high crystal quality necessary for good device performance. Further, because of the small bandgap of the (In,Ga)As layer, the need for a high AlAs mole fraction layer as in the GaAs/(Al,Ga)As MODFET is eliminated. The use of a low AlAs mole fraction layer allows for superior device performance at cryogenic temperatures. A growth technique using molecular beam epitaxy is described, with particular attention paid to the growth and optimization of the (In,Ga)As channel layer. Sheet carrier concentration, low- and midelectric field mobility and velocity-field characteristics, as well as electron saturation velocity, are determined as functions of various structural parameters, particularly InAs mole fraction. Photoreflectance measurements and theoretical calculations are used to describe the band structure in the (In,Ga)As quantum well. Finally, outstanding dc and microwave performances are demonstrated at room and cryogenic temperatures. These results indicate that the (In,Ga)As/(Al,Ga)As MODFET is a superior alternative to the GaAs metal-semiconductor field-effect transistor and GaAs/(Al,Ga)As MODFET for use as a high frequency, low noise amplifier and switch. Made available in DSpace on 2014-12-15T19:05:40Z (GMT). No. of bitstreams: 1 8908705.pdf: 4128814 bytes, checksum: 31b5f5aa68cbddfa67210f7466c1acf0 (MD5) Previous issue date: 1988 Embargo set by: Seth Robbins for item 69577 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 129 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988. http://hdl.handle.net/2142/69411 (UMI)AAI8908705 Engineering, Electronics and Electrical Analysis of the Indium Gallium Arsenide/aluminum Gallium Arsenide Modulation-Doped Field Effect Transistor text Electrical Engineering Electrical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.