VERFAHREN ZUM DOTIEREN VON HALBLEITERMATERIAL

摘要

1,169,188. Semi-conductor devices. MATSUSHITA ELECTRONICS CORP. 17 Oct., 1966 [10 Dec., 1965], No. 46349/66. Heading H1K. A diffusion process is performed through a mask having a plurality of apertures spaced by less than twice the diffusion depth of the impurity to form a single region. As shown, Fig. 2, a plurality of slots 8 in an oxide mask 2 may be used to produce a diffused region 6 the thickness of which varies over its area or, if the apertures are sufficiently close together to produce a substantially flat junction, the impurity concentration of the region is less than would be produced by the same diffusion through a single large aperture. The apertures may also be in the form of a pattern of squares, or may form a grid. In a silicon I.C., Fig. 4 (not shown), comprising a transitor, a Zener diode and a resistor diffused into N-type islands (11, 111,1111) isolated by a P-type region, the base region (13) of the diode, and the resistor (14) are produced simultaneously by a single diffusion and the emitter region 15 of the transistor and the anode region (17) of the diode are also produced simultaneously, by a further diffusion. The invention is applied to the production of the resistor (14) and the anode region (17) of the diode to obtain lower impurity concentrations in these regions. In a silicon I.C., Fig. 5 (not shown), comprising a pair of complementary junction transistors, the base region (31) of one of the transistors is produced using the method of the invention simultaneously with the emitter region (29) of the other transistor (which is produced using a single aperture). The base region (36) of a high frequency transistor, Figs. 6 and 7 (not shown), may be diffused using the method of the invention to produce a base-collector junction (37) the distance of which varies from the subsequently diffused plane emitter-base junction (39). This produces a base region with thin portions to obtain good h.f. characteristics and a high amplification factor, and thick portions to obtain a low lateral base resistance. The invention may also be applied to a silicon solar cell, Fig. 8 (not shown), to produce a region with thick and thin portions which has a low sheet resistivity without a large reduction in the penetration of sunlight.