| 摘要 |
842,403. Semi-conductor devices. SHOCKLEY TRANSISTOR CORPORATION. March 17, 1958 [March 18, 1957], No. 8480/58. Class 37. A semi-conductor device comprises a crystal having a plurality of grain boundaries along which extend extrinsic regions of opposite conductivity types which are in operative relationship. Fig. 1A shows a semiconductor crystal with three grain boundaries 11, 12 and 13, which may be grown by seeding to provide twin boundaries 11 and 12 with a small angle of tilt to give edge dislocations 14 to form large angle grain boundary 13. The crystal is then subjected to a first diffusion in the presence, for example, of an acceptor and then a second diffusion in the presence of a donor during which some of the diffused acceptor material will diffuse out. This results in an N-type region extending from the surface to a point at which acceptors begin to predominate forming a deeper P-type region. The diffusion extends mainly along the grain boundaries, as shown in Fig. 1B. Surface etching removes the outer layer to provide the arrangement shown in Fig. 1C with electrodes 17 and 18 associated with N-type zones and electrode 16 with a P-type zone. This structure may constitute an analogue transistor with electrodes 17, 18 and 16, functioning as cathode, plate, and grid respectively. Alternatively N-zones 17 and 18 may be arranged to join and form a PN junction with P-zone 16 to form a field effect transistor. If the P-zone 16 is arranged to lie between, and contact zones 17 and 18 a junction transistor is provided.
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