Surfaces - four zones transistor with a stromverstaerkung greater than one, in particular, for switching purposes

摘要

917,645. Semi-conductor devices. INTERNATIONAL BUSINESS MACHINES CORPORATION. May 24, 1960 [June 23, 1959], No. 18224/60. Class 37. In a PNPN semi-conductor switching device, the first three regions form a transistor with a current gain of between 0.2 and 0.4 and the second, third and fourth form a second transistor with a current gain of between 0.6 and 0.9; the overall gain is greater than unity. In Fig. 1, P-zone 13, N-zone 12 and P-body 14 form the first transistor section and NPN zones 12, 14 and 16 respectively form the second. The low current gain of the first section tends to provide a high-voltage breakdown while the large current gain of the second enhances current flow through the device when switched. Ohmic connections 18, 19 and 20 are made to zones 13, 14 and 16, respectively. Fig. 3 shows a circuit comprising the device which is maintained non- conducting by a negative bias to zone 14 from battery 30. When a positive pulse is provided from generator 33, the device conducts to operate relay 32. The zone structure may be produced providing N-type layers 12 and 16 on P-type body 16 by diffusion, alloying leadantimony dot 23 to zone 16 to provide an ohmic contact thereto, alloying dot 21 of leadgallium alloy and indium dot 22 simultaneously to provide P-type zone 13 on N-type layer 12 and ohmic contacts to the P-type zone 13 and P-type zone 14. In a modification, a dot comprising lead antimony and gallium or lead, antimony and indium is used to provide P and N regions in one post-alloy diffusion operation. The alloy may consist of 0.6 to 1% of antimony, 0.0025 to 0.0075% of gallium, the balance being lead.