DTIC ADA1014700: Continuation of Study of Heterojunction pdf

DTIC ADA1014700: Continuation of Study of Heterojunction

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AlGaAs/GaAs heterojunction gate GaAs FETs have been fabricated with molecular beam epitaxy (MBE) and organometallic vapor phase epitaxy (OM-VPE), which allow for enhanced uniformity and reproducibility. The best results were obtained with MBE n-GaAs active layers and OM-VPE gate layers of p+-AlGaAs and p+-GaAs. Process steps such as a plasma ash and in situ heat cleaning of the mesa-etched layer before OM-VPE gate growth must be taken in order to ensure that the interface is clean and free of carbon contamination. Moreover, a very thin (200 A) p+-GaAs layer between the n-GaAs channel and the p+-AlGaAs helps to isolate the actual p+n gate junction from oxygen that is gettered into AlGaAs grown by OM-VPE. C-V measurements indicate a 1.3V built-in voltage for this junction, while forward I-V characteristics give a nonideality factor n = 2 and are similar to those of a GaAs p+n junction. Thus the electrical characteristics of the heterojunction are retained, along with the advantages of selective undercut etching and self-aligned metal

• Creator/s: Defense Technical Information Center
• Date: 5/1/1981
• Year: 1981
• Book Topics/Themes: DTIC Archive, Maloney, Timothy J, VARIAN ASSOCIATES INC PALO ALTO CA SOLID STATE LAB, *GALLIUM ARSENIDES, *FIELD EFFECT TRANSISTORS, METALS, MEASUREMENT, LAYERS, PLASMAS(PHYSICS), HETEROJUNCTIONS, GATES(CIRCUITS), ORGANOMETALLIC COMPOUNDS, EPITAXIAL GROWTH, CARBON, VAPOR PHASES, ETCHING, ELECTRICAL PROPERTIES, MOLECULAR BEAMS, ALIGNMENT, OXYGEN, SELF OPERATION, CLEANING, CONTAMINATION, HEAT, JUNCTIONS, REPRODUCIBILITY, ASHES

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