| 摘要 |
1,030,048. Semi-conductor devices. SIEMENS & HALSKE A.G. Sept. 29, 1964 [Sept. 30, 1963], No. 39541/64. Heading H1K. A semi-conductor unit is produced by diffusing gaseous dopant of one type into opposite surfaces of a semi-conductor body of the opposite conductivity type, one surface being masked to limit the diffusion to an annular zone, the process being such that the diffusion joints meet to isolate a region of the original conductivity type inside the annulus. In one embodiment an N-type silicon wafer which has one face lapped and one polished to provide different rates of diffusion is covered with silicon oxide which is then removed from the lapped face and from an annular region, 3, on the polished face. Diffusion is effected with boron trioxide vapour to form P-type regions 7 and 9; the diffusion is effected in two steps, firstly in the presence of the dopant vapour and then in oxygen which results in further diffusion and the provision of a new oxide layer 3 over the diffused region. Diffusion is continued until the two P-regions meet leaving an N-type island 8. A semi-conductor diode may be provided by alloying a metal layer 4 to the N-type region 8 to form an ohmic contact for terminal member 13. Similarly metal layer 11 provides ohmic contact to P-region 7 for base-plate 12. A further embodiment consists of a transistor in which terminal 13 is associated with a further P-type zone extending into N-type base region 8 which is provided with an annular ohmic base contact. Phosphorus pentoxide or trioxide may be used to form N-type regions and germanium or A 3 B 5 compounds may be used in place of silicon. Indium, gallium, zinc, antimony and arsenic may also be used for diffusion.
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