| 摘要 |
1,133,812. Semi-conductor devices. SIEMENS A.G. 15 June, 1967 [16 June, 1966], No. 27656/67. Heading H1K. In order to prevent vaporization from the surface of a semi-conductor body during masked diffusion of a P-type dopant, the diffusion is carried out in a chamber containing a partial pressure of the semi-conductor material concerned. The invention is particularly applicable to the diffusion of Al and/or B into Ge, which requires a temperature of 600-930‹ C. The Ge partial pressure may be provided, as shown, by powdered Ge/Al and/or B alloy 3 surrounding the Ge wafers 4 in an evacuated quartz tube 1. The alloy may be contained in a Ta box. Alternatively the tube itself may be coated with Ge, or the diffusion may take place in a sealed Ge tube contained within a further sealed tube. A carrier gas such as argon or neon saturated with Ge may also be used. The masking material for the Ge wafers may be Si 3 N 4 or SiO 2 , the latter being formed by pyrolytic decomposition of silane. The SiO 2 may be mechanically stabilized by P, included by mixing phosphine with the silane. The Ge/Al and/or B alloy is prepared by alloying Ge with the dopant, and pulverizing the alloy. The alloy may also be treated with acid and annealed. The technique described may be used in the manufacture of planar Ge diodes, transistors or integrated-circuits, conventional photoresist masking methods being adopted. Other dopants referred to are As, Sb, In, Ga and Zn. |
