| 摘要 |
1,221,882. Semi-conductor devices. TELEFUNKEN PATENTVERWERTUNGS G.m.b.H. 31 May, 1968 [1 June, 1967], No. 26265/68. Heading H1K. In a process of diffusing impurity into a semiconductor through a hole in a masking layer, an intermediate layer of material in which the impurity diffuses more rapidly than in the semiconductor is disposed between the mask and the semi-conductor. When diffusing indium, gallium or aluminium into germanium silicon nitride and silicon dioxide are suitable for use in the masking and intermediate layers respectively. A PN diode made by diffusing into an oxide coated N-type body through a nitride mask has a high breakdown voltage due to lateral spread of the diffusant through the oxide around the aperture. This spread can be limited by restricting the oxide to a small area surrounding the aperture. A transistor is made from the diode structure by forming an aperture in the oxide after the acceptor diffusion and diffusing donor impurity through it. Alternatively a PN junction isolated transistor can be formed in an N-type body by first diffusing indium through an aperture in a nitride mask to form a P zone 9 (Fig. 7) defined by the area of oxide layer 2 and then diffusing gallium at a higher concentration into the centre of this area to form P + region 8. Finally the base is formed by making a larger hole extending through the nitride and oxide and diffusing donor impurity through it to over-compensate region 5 while leaving region 8 P-type to constitute the emitter. |
