An Electron Beam Method for Measuring High Sheet Resistances of Thin Films

Measurement of sheet resistances of high resistance (up to 1016 Ω/□) thin films using conventional methods is both difficult and subject to error. We have developed a method for making sheet resistance measurements in which a low velocity electron beam is used to inject charge into the film. The inj...

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Bibliographic Details
Published in:Review of scientific instruments 1970-12, Vol.41 (12), p.1817-1824
Main Authors: Chester, A. N., Kosicki, B. B.
Format: Article
Language:English
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Summary:Measurement of sheet resistances of high resistance (up to 1016 Ω/□) thin films using conventional methods is both difficult and subject to error. We have developed a method for making sheet resistance measurements in which a low velocity electron beam is used to inject charge into the film. The injected charge drifts under the influence of its self‐induced field to metal electrodes evaporated on the film, where it is collected and measured externally as a time dependent current. We give examples of thin GaAs films for which the measured current can be fit with a current predicted by a simple model over many orders of magnitude by adjusting only one parameter, the sheet resistance of the film. The good agreement between experimental and theoretical currents provides reliable values for the sheet resistance. This allows an estimation of a lower limit on the carrier density native to our GaAs films.
ISSN:0034-6748
1089-7623
DOI:10.1063/1.1684418