Semiconductor devices

摘要

1,005,917. Semi-conductor devices. NATIONAL RESEARCH DEVELOPMENT CORPORATION. April 26, 1962 [April 27, 1961], No. 16263/61. Heading H1K. A semi - conductor device comprises a laminar of semi-insulating GaAs having a resistivity greater than 105 ohm/cm. with a metal contact on one face and a layer of semi-conductor containing a PN junction on the other and an electrically conducting spike extruding between the contact and the semi-conductor material. The high resistivity material may be obtained by floating zone refining or by heating in oxygen to 1100‹ C. for 12 hours. Fig. 7 shows a P-type layer s of semi-conductor such as gallium arsenide or germanium produced by epitaxial deposition on the laminar e of semi-insulating gallium arsenide. The deposition may be effected by using iodine vapour or a saturated solution of gallium arsenide in gallium; zinc may be added to the gallium arsenide to render it P-type. A pellet of tin or antimony-tin is then alloyed to the centre of the P-type layer to form an N-type region and the heating is continued until the metal forms a stalk g extending right through the insulating gallium arsenide to contact metallic layer f. This penetration may be assisted by crystal orientation, ´ndueed dislocations such as by ultrasonic machining, heating by electric current or first boring a hole through the material. The PN junction region is then etched to provide a cut-away portion as shown. An ohmic contact h is provided to the P-type layer s. The arrangement may be adapted for coaxial fitting as shown in Fig. 8. Fig. 9 shows an attractive arrangement in which a goldplated molybdenum plate f is provided with a spiked portion g which contacts the alloy pellet a.