| 摘要 |
1424917 Plasms-oxidation; coating with metals UNIVERSITY OF TOKYO 8 Oct 1973 [12 Oct 1972] 46860/73 Headings C7F and C7U [Also in Division H1] Dielectric isolation of an epitarial layer of a compound semi-conductor of GaAs, GaP, or gallium arsenide-phosphide is provided by forming a film of said semi-conductor on a semi-insulative substrate, evaporating an A1 mask layer on to the surface of the film, selectively removing Al by a photo-resist process from areas to be oxidized, and oxidizing the exposed semi-conductor by high frequency hot plasma discharge at 1000- 1300‹C in an O 2 atmosphere to a depth to reach the substrate, or to cross a pn junction formed in GaP or Ga arsenide-phosphide, the pressure of O 2 being about 0À3 Torr for GaAs and 0À4-0À6 Torr for the other cases. For GaAs the voltage is 6-7 KV and otherwise is about 8KV; oxidation may be to a depth of about 10Á. A GaAs layer 9 is vapour coated with A1 layer 10, part of which is removed by a photo-resist process (step b) prior to plasma oxidation to produce oxidized regions 11, which is followed by removal of the Al with HF (step d) and vacuum-coating with In electrodes ABC and G. A similar process is described regarding Fig. 4 (not shown), where the substrate is N-type CaAs, and is covered with a thin P-type layer of GaAs doped with Zn; processing is as above.
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