Development of Thin-Film Active Devices on an Improved Insulating Substrate.
Abstract
A scanning electron microscopic study has been made of the early stages of epitaxial silicon growth on stoichiometric Czochralski and low alumina rich flame fusion spinel. It is observed that the silicon reacts with the Czochralski spinel appreciably more than with the flame fusion material prior to complete coverage of the substrate surface. The degree to which the reaction takes place appears to be a function of the composition of the substrate crystal. A back to back through diffused junction test structure has been adopted to monitor the development of processing techniques in silicon on spinel and to characterize the electrical properties in a manner applicable to MOS device fabrication. Junction spacings of 0.2, 0.4 and 1.0 mil are employed in each test pattern. Operative diodes can be made using the 0.2 mil spacing, which indicates that anomalous diffusion of dopants at the silicon-substrate interface has been minimized. The diffusion coefficient of phosphorus in the silicon on spinel, for a phosphorus doping level of 10 to the 20th power/cc, is typically about 3 x 10 to the 13th power sq cm/sec. This value is double that of phosphorus in bulk silicon, but about half the value commonly observed in silicon films on sapphire. A nondestructive capacitance technique is under development to examine the origin of interface inversion layers which sometimes appear during device processing.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1969
- Accession Number
- AD0859110
Entities
People
- Glenn W. Cullen
Organizations
- Sarnoff Corporation