Semiconductor devices

摘要

940,681. Semi-conductor devices. WESTING- HOUSE ELECTRIC CORPORATION. Nov. 3, 1960 [Nov. 10, 1959], No. 37808/60. Heading H1K. In a semi-conductor device with a P+N+NP or N+P+PN zone configuration the P+ and N+ zones have an uncompensated activator concentration of at least 1019 atoms/cc. and form a tunnel junction. The device exhibits a negative registance between electrodes provided on the outer zones which is controllable through a further electrode attached to the inner N+ or P+ zone. A typical device is produced by heating a wafer of 200 ohm. cm. P-type silicon to 1200‹ C. in a diffusion furnace containing gallium vapour to produce a P+ surface zone 1 mil. thick containing 1019 atoms/c.c. of gallium which is then removed except from one face of the wafer. Phosphorus is then diffused into the central part of said one face to form an N-type region less than a mil. thick by heating the wafer to 1250‹ C. in phosphorus vapour. A pellet 18 (Fig. 5) consisting of 99.5 % by weight gold and 5% atimony is alloyed at 750‹ C. to the opposite face of the wafer, an antimony-gold contact attached to the N-type region and an annular aluminium-antimony contact attached to the gallium doped layer to complete the device. In an alternative method the N region is made by alloying a pellet of 99.5% gold and 5% arsenic to the P + zone by heating to 650-750‹ C. in vacuum, argon or helium. Removal of unwanted parts of the P+ region may be avoided by suitable oxide masking of the wafer before the gallium diffusion step. Devices using germanium, silicon carbide, and A III B V compounds such as gallium arsenide and indium antimonide are also envisaged.