Method for epitaxial growth of GaAs films and devices configuration independent of GaAs substrate utilizing molecular beam epitaxy and substrate removal techniques

A method of growing high-quality super-abrupt thin-film epitaxial layers to form a composite comprising:

• polishing one surface of a high-resistivity, low-dislocation-count, germanium substrate,
• placing said polished germanium substrate into a vacuum deposition system,
• evacuating said system to a high vacuum,
• outgassing said substrate by heating said evacuated system to a temperature greater than a molecular beam epitaxial growth temperature,
• lowering the temperature of the system to the molecular beam epitaxial growth temperature for GaAs,
• growing a thin layer of n-doped GaAs onto said polished surface of said germanium substrate from a n-type doping source,
• abruptly shutting off said n-type doping source,
• simultaneous with shutting off said n-type doping source, initiating the growth of a semi-insulating layer without interrupting the GaAs growth process to obtain a layer of desired thickness,
• growing a thin layer of germanium onto said semi-insulating layer,
• reheating said doped substrate sufficiently to deposit a layer of gold onto said thin germanium layer to form a gold-germanium alloy,
• removing the layered substrate from said vacuum system and bonding the gold-germanium layer to a carrier substrate,
• applying a protective coating to the ends and edges of said composite up to said germanium substrate,
• etching said germanium substrate from the layered substrate, and
• etching said GaAs layer to tailor said GaAs layer to a desired thickness,
• whereby said GaAs layer may be photolithographically processed to form desired structures such as GaAs field-effect-transistors.