| 摘要 |
774,388. Semi-conductor devices. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Dec. 21, 1954 (Jan. 28, 1954], No. 2665/54. Class 37. A method of manufacturing junction transistors comprises (i) forming a semi-conductor body with a grown junction between P and N type materials; (ii) electrolytically etching said body to produce by differential etching a visible step where the junction is situated; and (iii) providing at least one emitter junction on at least one side of the grown junction at a predetermined distance therefrom. " Emitter junction " is defined as one in which a bulk alloying impurity is positioned on a single crystal semi-conductor and heat is applied to produce a fused alloy type of junction. The grown junction may be formed by crystal pulling or zone melting. In one embodiment for producing an NPN transistor (Figs. 1-4) a semiconductor PN bar (Fig. 1) is electrolytically etched to produce a step or shoulder 2 (Fig. 2) at the grown junction 1. The P type material is then partly removed and a recess or well 3 (Fig. 3) is formed by ultrasonic drilling in the remaining P type material. A pellet 5 of antimony is placed in the well 3 and heated to 550‹ C. for about 10 minutes to diffuse into or alloy with the P type material and form the required N type alloy or emitter junction. The antimony pellet 5 together with the emitter and base connection is encased in silicone resin 8 and finally the whole device (with the collector connection soldered on at 9) is impregnated with silicone resin. In the electrolytic etching process to produce the step 2 the bath may be KOH or H 2 0 2 and the current passed through the PN bar causes removal of material from the P and N portions at substantially different rates and accordingly the visible step 2 (shown exaggerated) is produced in the plane of the junction 1. The emitter and base connections 6 comprise gold wires soldered to the antimony pellet 5 and to a flat connector 7 on the ground face 4 and encircling the well 3. Chemical and electrolytic etching may be employed to clean the semi-conductor at various stages in the process. If desired a second emitter junction may be provided on the other side of the grown junction 1 to produce a double or cascade transistor. PNP transistors may be manufactured, Figs. 5 to 7 (not shown), using the same basic process as illustrated in Figs. 1 to 4 and in this case indium to form the emitter junction. |
