Accession Number:

ADA218730

Title:

Fundamental and Practical Studies of Metal Contacts on Mercury Zinc Telluride

Descriptive Note:

Final technical rept. 1 Sep 1986-31 Aug 1989,

Corporate Author:

STANFORD UNIV CA STANFORD ELECTRONICS LABS

Personal Author(s):

Report Date:

1989-08-31

Pagination or Media Count:

29.0

Abstract:

How the metal overlayer grows and chemically interacts with the substrate in metalII-VI systems such as Cadmium Telluride and Zinc Telluride has practical importance for the electrical characteristics of metal contacts to these materials. By studying metal interfaces with these binaries, we gain insight into the role of the weak Mercury-bonding in the alloys Mercury Cadmium Telluride and Mercury Zinc Telluride during metal contact formation, where severe Hg depletion on the order of 20-60 from the top few layers of the HgCdTe substrate is typically observed upon metal deposition. We report results of our comparative study of the interfacial chemistry and band bending behavior for Aluminum, Indium, Silver, and Platinum overlayers on vacuum-cleaved p-CdTe and p-ZnTe110 using both UPS and XPS. A range of metal-substrate reactivities have been considered Al reacts strongly with Tellurium, Ag moderately, and In minimally, with no evidence seen for In reaction on ZnTe. Pt exhibits strong alloying behavior with both Cd and Zn. We compare these results for the binaries to metalHgCdTe interface formation. We find that Hg loss can significantly influence the extent of reaction andor intermixing for these overlayers, with resulting disruption either inhibiting or facilitating chemical interaction. We consider band bending at these metalCdTe and metalZnTe interfaces to correlate Fermi level movement in the bandgap during metal deposition with interfacial chemistry and morphology of the overlayer. aw

Subject Categories:

  • Physical Chemistry
  • Electrical and Electronic Equipment
  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE