| 摘要 |
1,101,563. Semi-conductor devices. GENERAL ELECTRIC CO. 8 April, 1965 [28 May, 1964], No. 14926/65. Heading HlK. The surface of a diamond is made semiconducting by exposing it to ionic bombardment produced by a brush discharge in a gas. The anode and cathode of the discharge apparatus may be of nickel or molybdenum and the cathode, on which the diamond rests, may be agitated to expose the whole surface of the diamond to the gas ions. The processed diamond is found to be coated with a film of sputtered cathode metal which is removed with aqua regia. A surface layer of the diamond is found to be quasi-amorphous and exhibits semiconductivity. Several examples are given, an atmosphere of nitrogen or argon producing an N-type surface, an atmosphere of hydrogen producing a P-type surface, and an atmosphere of helium or oxygen producing a resistive surface. An N-type surface layer may be produced in a P-type diamond doped with aluminium, indicating the possibility of producing diodes and transistors. On heating for a short time at a high temperature and pressure, or for about an hour at 300‹ to 400‹ C., in air, the diamonds lose their semi-conductive properties. Diamonds treated with a hot mixture of sulphuric acid and potassium nitrate to remove any graphite, amorphous carbon, or other non- diamond impurities from the surface increase in resistivity without losing their semi-conductive properties. It is stated that diamonds merely containing hydrogen or nitrogen as an impurity do not exhibit semi-conductivity. |
