Growth of extremely uniform layers by rotating substrate holder with molecular beam epitaxy for applications to electro-optic and microwave devices

Abstract

Integrated optics and integrated microwave circuits require extremely uniform epitaxial layer thicknesses, composition profiles, and doping profiles. With a sample rotating mechanism, molecular beam epitaxy can for the first time prepare GaAs and Al_xGa_1−xAs layers with thickness variation of less than 1% over a lateral dimension of 5 cm. The variation of AlAs mole fraction of the Al₀.₃Ga₀.₇As over a 10‐cm² area was less than 0.4%. The variation of the ’’pinch‐off’’ voltage for a field effect transistor structure was less than 1.4% over a 10‐cm² wafer. These results represent the most uniform epitaxial layers ever prepared with any crystal growth technology.