A METHOD OF PREPARING SEMICONDUCTOR SUBSTRATES

摘要

A new method for GaAs substrate preparation which significantly reduces the formation of oval defects during MBE growth of selectively doped n-AlxGa1-xAs/GaAs heterostructures. The method simply requires treatment in H2SO4 after mechano-chemical polishing in NaOCl solution and generation of a protective surface oxide during in soldering. Routinely a density of oval defects of less than 200 cm-2 is achieved for 2- mu m thick heterostructures. The efficiency of the new preparation procedure is demonstrated by 2DEG mobilities in excess of 106 cm2/Vs at 6K obtained with a spacer width as narrow as 18 nm.