Ellipsometric characterization of multilayer transistor structures

John A. Woollam, Paul G. Snyder, Kenneth G. Merkel, Samuel A. Alterovitz

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Variable angle spectroscopic ellipsometry has been used to determine layer thicknesses, alloy compositions and lateral homogeneity in the relatively complex semiconductor multilayer structures used for modulation-doped field effect transistors. Specifically, we have simultaneously determined five GaAs/AlxGa1As layer thicknesses and the alloy compositions x in two of these layers. Good fits between experimental data, and predicted data based on parameter-dependent models were found. In a system with seven unknown ellipsometric parameters to be solved there is potential for the correlation of variables. Thus, we have made a careful study of correlation and the dependence of solved parameter values on the mean-square error value determined in the regression analysis. Lateral homogeneity of molecular beam epitaxial-grown layer thicknesses in similar structures has also been investigated.

Original languageEnglish (US)
Pages (from-to)291-294
Number of pages4
JournalMaterials Science and Engineering B
Issue number2
StatePublished - Jan 1990

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


Dive into the research topics of 'Ellipsometric characterization of multilayer transistor structures'. Together they form a unique fingerprint.

Cite this