in one form of the invention , a method for the growth of an epitaxial insulator - metal structure on a semiconductor surface comprising the steps of maintaining the semiconductor surface at a pressure below approximately 1 × 10 - 7 mbar , maintaining the semiconductor surface at a substantially fixed first temperature between approximately 25 ° c . and 400 ° c ., depositing an epitaxial metal layer on the semiconductor surface , adjusting the semiconductor surface to a substantially fixed second temperature between approximately 25 ° c . and 200 ° c ., starting a deposition of epitaxial caf 2 on the first metal layer , ramping the second temperature to a third substantially fixed temperature between 200 ° c . and 500 ° c . over a time period , maintaining the third temperature until the epitaxial caf 2 has deposited to a desired thickness , and stopping the deposition of epitaxial caf 2 on the first metal layer .