| 摘要 |
1,087,134. Semi-conductor devices. MULLARD Ltd. June 23, 1964 [July 17, 1963], No. 28298/63. Heading H1K. A heterojunction semi-conductor device is made by forming on a body of an A III B V compound or a mixed crystal of two or more such compounds (e.g. GaAs x P 1-x ) a melt comprising said compound or mixed crystal and another A III B V compound and a carrier material and recrystallizing to form an epitaxial layer consisting of a solid solution thereof. In a typical example an alloy of bismuth, 80 parts by weight, and gallium antimonide 20 parts, is placed on one face of a tellurium doped N-type gallium arsenide wafer and an alloy of bismuth, tin and platinum on the other. After etching in a solution of bromine in methanol the assembly is heated at 550� C. for 2 hours and then cooled over a period of 3 hours. After etching again platinum wires are soldered to the alloy residues to complete a rectifier diode with a PN heterojunction. A photo-diode is similarly formed but using an alloy of bismuth 78 parts by weight, cadmium 2 parts and indium arsenide 20 parts to form the PN heterojunction. In this case heating is to 580� C. for an hour and the cooling period is 4 hours. It is also suggested to use the method to form a collector junction of lower energy gap in a transistor, e.g. a light link transistor, and to use lead, tin or cadmium, or bismuth-tin or bismuth tinplatinum alloys in place of bismuth as the carrier material in which significant impurities may be incorporated to provide the desired conductivity characteristics in the recrystallized region. A number of suitable alloy compositions are specified. |
