| 摘要 |
916,948. Semi-conductor devices. INTERNATIONAL BUSINESS MACHINES CORPORATION. June 26, 1959 [June 27, 1958; Aug. 27, 1958], No. 21957/59. Class 37. A method of making a junction with a semiconductor body comprises applying to the body a metal which is neither donor nor acceptor, and in which the semi-conductor is soluble, heating to form a pool of the metal and dissolved semi-conductor, exposing the pool to an atmosphere containing a donor or acceptor and cooling to solidify the pool. In one embodiment lead is placed on top of a 5 ohm cm. P-type germanium body and heated to 700‹ C. whereupon it melts and dissolves the surface germanium. During the heating the acceptor impurity in the body diffuses into the lead to leave the germanium immediately beneath the lead substantially free of acceptors and hence of intrinsic resistivity. After reducing the temperature to 500‹ C. to partially recrystallize the germanium, arsenic vapour is introduced which rapidly dissolves in the lead. When the assembly is subsequently cooled the recrystallizing material therefore contains an excess of arsenic and is N-type. In a method of making an NPN transistor a P-type layer is produced by diffusion of acceptors into one surface of an N-type body including both donors and acceptors. Subsequently lead is placed on the P-type layer and heated while maintained in a donor, e.g. arsenic-containing, atmosphere to partially dissolve the semi-conductor. The donors preferentially diffuse outwards into the molten lead to leave a P-type layer forming an extension of the layer formed by diffusion. Simultaneously donor impurity from the atmosphere dissolves in the lead so that on recrystallization an N-type layer forms above the P-type layer. |
