Accession Number:



A Novel Approach to Silicon-on-Insulator Materials

Descriptive Note:

Final Technical rept.

Corporate Author:


Personal Author(s):

Report Date:


Pagination or Media Count:



There is currently a great deal of interest in insulator on semiconductor layer constructions in the electronics community. Calcium fluoride is electronically insulating and lattice matched to both silicon and gallium arsenide, which makes it an ideal insulator for these materials. Also, CaF2 is being used as an insulator with thin films of the high temperature superconducting materials. While there has been a great deal of work in the deposition of CaF2 films by physical techniques, such as molecular beam epitaxy MBE, this technique is not considered to be viable for large scale production techniques due to the expensive and sophisticated high vacuum equipment involved. Another problem with MBE of CaF2 is that high substrate temperatures greater than 500 C seem to be required for good quality films. Due to the differences in thermal expansion between CaF2 and silicon or gallium arsenide, these films tend to crack when cooled to ambient temperature. Therefore, a project was undertaken to see if CaF2 films could be grown by chemical methods. The most useful of these is the Chemical Vapor Deposition CVD method, where the material of interest is produced by a chemical reaction on the substrate surface by one or more precursor molecules, which are delivered to the substrate in the gas phase. For a binary material, such as CaF2, there are two CVD growth methods. In a dual source method, two precursors are used, each of which contains one of the elements in the film material. In the single source technique, a precursor molecule which contains both elements that comprise the film material is used. This report will describe work in which each approach was tried.

Subject Categories:

  • Electrical and Electronic Equipment

Distribution Statement: