| 摘要 |
780,724. Semi-conductor devices.LICENTIA PATENT-VERWALTUNGS-GES. Aug. 24, 1953 [Aug. 18, 1952], No. 21704/55. Divided out of 780,723. Class 37. A method of making an asymmetrically conducting device comprises imparting to at least one region of a semi-conductor body, e.g. Ge or Si of one conductivity type conductivity of the opposite type by passing a thermal forming current into the region through an electrode in contact therewith and then removing a surface layer at least of the converted region. The surface layer may be removed by chemical etching, e.g. using a mixture of HF,HN0 3 ,CU(N0 3 ) 2 and water as etchant for Ge, or by electrochemical etching using as electrolyte e.g. a 10-70 per cent aqueous solution of H 3 PO 4 on Ge, the treatment being preferably effective over the entire surface of the body and being carried on longer on the unconverted regions. After etching the body is subjected to heat, preferably in vacuum or a protective atmosphere. In the embodiment two converted regions 8, 9 are formed which overlap, the etching being carried on until the overlapping region is removed and the nearest parts of the converted zones are a few Á or a few 10Á apart. Pointed electrodes 12, 13, at least the contact surfaces of which consist of nickel, nickel alloy or a noble metal or alloy thereof, particularly gold, are inserted into the respective cavities produced by the electro forming. Additional electrodes may also be placed on the unconverted regions adjacent the cavities. |
