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Elimination of long-term calibration drift in molecular beam epitaxy by cooling the source flange

Drift-Eliminierung der Langzeit Kalibrierung bei der MBE durch kühlen der Quellenflansche
: Larkins, E.C.; Thaden, H.; Betsche, H.; Eichin, G.; Ralston, J.D.


Journal of vacuum science and technology B. Microelectronics and nanometer structures 12 (1994), Nr.6, S.3220-3222 : Abb.,Lit.
ISSN: 0734-211X
ISSN: 1071-1023
Fraunhofer IAF ()
Bauelemente-Technologie; device technology; III-V Halbleiter; III-V semiconductors; MBE

Drifts in the growth rate calibration with time constants of the order of hours are observed during molecular beam epitaxy growth, adversely influencing the calibration stability and reproducibility.'Me principal cause of these drifts was found to be high, time-dependent source flange temperatures ( bigger than 40 degree Celsius) at the thermocouple feedthroughs.'Re installation of water-cooled blocks on the furnace flanges eliminated this long-term drift and improved the calibration reproducibility by a factorof 3. In addition, these cooling blocks significantly reduced the ion-pump current in the growth chamber, presumably due to reduced outgassing of the source flange.