Method of preparing semiconductor substrates

US4732648A · kind A · utility

Assignee

• Max-Planck-Gesellschaft zur Föderung der Wissenschaften e.V. · US

Inventors

• Hans Fronius · Stuttgart, DE
• Albrecht Fischer · Löchgau, DE
• Klaus Ploog · Stuttgart, DE

Key dates

• Filing date: Dec 16, 1986
• Grant date: Mar 22, 1988
• Expiry date: Dec 16, 2006

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/30625
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A new method for GaAs substrate preparation which significantly reduces the ormation of oval defects during MBE growth of selectively doped n-Al.sub.x Ga.sub.1-x As/GaAs heterostructures. The method simply requires treatment in H.sub.2 SO.sub.4 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.sup.-2 is achieved for 2-.mu.m thick heterostructures. The efficiency of the new preparation procedure is demonstrated by 2DEG mobilities in excess of 10.sup.6 cm.sup.2 /Vs at 6K obtained with a spacer width as narrow as 18 nm.