| 摘要 |
917,773. Semi-conductor devices. PHILIPS ELECTRICAL INDUSTRIES Ltd. Aug. 4, 1959 [Aug. 7, 1958], No. 26566/59. Class 37. In the alloy-diffusion process, in which a material containing a segregating impurity of one type is alloyed to a semi-conductor body and at the same time a diffusing impurity of the other type is diffused into the body via the liquid-solid interface, that region of the diffused zone which is partly compensated by diffusion of the segregating impurity is eliminated by melting to a least half its depth by a subsequent short thermal after-treatment. As shown in Fig. 1, a pellet 2 containing 94% neutral Bi or Pb, 5% segregating impurity A1 and 1% diffusing impurity As is alloyed to a semiconductive body 1 of P-type Ge by heating at 760 C. in a neutral atmosphere, for 15 minutes. On cooling an alloy zone of P-type Ge, doped with A1, is formed, together with the diffusion zone 4 of N-type Ge, doped with As. Arsenic is also diffused into a surface zone 5, either from the material 2 or from a surrounding atmosphere, the zone 5 enabling connection to be made to the zone 4. During the process some Al diffuses into the body 1 and partly compensates the effect of the As in the diffused zone 4. Fig. 2b shows the modulus of the difference between the number of acceptors N a and the number of donors N d in various regions and whereas to the left of point 14 and to the right of point 19 acceptors predominate to form the P-type conductivity, the region 14-16 between shows the partial compensation of the impurities in the N-type zone. The diffusion penetration depth of Al is about 0.2Á and the partly compensated region is eliminated, as shown in Fig. 2c, by a thermal after-treatment with an increase in temperature of 2 C. over the alloy diffusion temperature of 760‹ C. for 30 seconds. An ohmic connection to the base zone 4 may be made via surface zone 5 by means of an annular contact 10 of 99% Pb and 1% As. The body 1 is soldered to a Ni connector 7 by a galliumindium alloy 8. The process is applicable also to silicon and Group III/V alloys, and to the manufacture of PNP or NPN transistors, " Hook " transistors, or devices in which the diffused layer is a drift region of the same type as the semi-conductor. |
