| 摘要 |
744,929. Semi-conductor devices. SYLVANIA ELECTRIC PRODUCTS, Inc. Juno 19,1953 [June 19, 1952], No. 16999/53. Class 37. An electrical translating device comprises a PN junction produced by bringing a semiconductor body of one conductivity type, into contact with a heated mixture containing the semi-conductor to saturation point and an impurity of the opposite conductivity type, the mixture having a melting point below that of the solid semi-conductor. In Fig. 2, pure germanium is added to pure antimony liquid 12 until the molten mixture is saturated, and a small additional quantity of germanium 14 is added to ensure the melt remains saturated with germanium. The respective proportions of antimony and germanium may then be controlled by controlling the temperature of the melt. A slab of P-type germanium 10 is introduced into the melt, so that the donor impurity antimony diffuses into the solid germanium to convert part of it to N-type. The extent of diffusion can be accurately controlled by varying the time and temperature. In an alternative process, the melt is cooled during the treatment so that N-type germanium material heavily doped with antimony forms on the surface of the P-type germanium body. Fig. 3 shows the germanium body after diffusion treatment having P and N portions of material. The body may then be used as a rectifier, or if the ends and edges are cut away, as a junction transistor having collector and emitter electrodes 16 and 20, and base electrode 18. Silicon may be used instead of germanium. Aluminium, gallium and indium are specified as suitable acceptor impurities, and phosphorus, arsenic and nitrogen as donors. Tin may be used in conjunction with a small amount of boron or other donor or acceptor impurity, to decrease the melting point of the mixture without involving excess concentrations of impurity in the resulting material. The mixture may be applied to the surface of the semi-conductor as a pellet, alloy or as powders and then heated. Photo-electric effects are referred to. |
