| 摘要 |
1,174,702. Semi-conductor devices. MOTOROLA Inc. 9 May, 1968 [29 May, 1967], No. 22077/68. Heading H1K. [Also in Division C7] Si or Ge are deposited on sapphire by the decomposition of silane or germane while maintaining the sapphire at 850-970‹ C. for silane and at 550-670‹ C. for germane. After depositing at least 0À2 micron of Si or Ge the sapphire temperature may be raised to 1000- 1300‹ C. for Si deposition or 700-850‹ C. for Ge deposition and the further deposition may be effected with silicon and germanium tetrachlorides and trichlorosilane or trichlorogermane. Deposition is preferably made on the (1012) plane of the sapphire which may first be cleaned by gas etching with ClF 3 in H 2 at 1200‹ C. The epitaxial layer may be doped as it grows by adding phosphine, diborane or arsine to the carrier gas which is H 2 , He or N 2 . Fig. 1 shows a furnace 11, a quartz tube 13, RF induction coils 14 and sapphire wafers 16 on a graphite susceptor 17. A SiO 2 layer may first be deposited on the sapphire by the reaction of oxygen and silicon tetrachloride in the decomposition of ethyl orthosilicate. Selected areas of the SiO 2 are then removed and the Si or Ge are then deposited on the selected areas. The polycrystalline Si or Ge deposited on the remaining SiO 2 layer is then removed by polishing. The structure is used in the assembly of transistors, rectifiers and integrated cir cuits. |
