| 摘要 |
1,255,576. Making semi-conductor structures. SIEMENS A.G. 18 Feb., 1970 [19 Feb., 1969], No. 7704/70. Heading H1K. The components 5 for a silicon-doped gallium arsenide melt are placed in a silica or carbon capsule on the end of which is an N-type gallium arsenide substrate 4 secured by the threaded cap 2. The capsule is placed in a silicon ampoule 1 which is evacuated and sealed so that the subsequent preparation of the melt and a deposition process may be carried out in an oxygen-free atmosphere formed (mainly) by the vapour from the heated gallium arsenide. The melt components are fused at 970� C. and the ampoule inverted to deposit the melt on the substrate and the assembly allowed to cool. Silicon is an amphoteric dopant in gallium arsenide and the material deposited with a melt temperature above 920� C. is N-type but later growth is P-type. Deposition is stopped by again inverting the ampoule when the melt temperature has fallen to 500� C. The melt may be reheated and the process repeated to form an alternating sequence of N-type and P-type layers on the initial substrate. The conditions are chosen to be such that the deposited gallium arsenide contains 1-2 at. per cent of silicon. |
