United States Patent 3,468,729
September 23, 1969

Method Of Making A Semiconductor By Oxidizing And Simultaneous Diffusion Of Impurities Having Different Rates Of Diffusivity
Walter C. Benzing

Filed March 21, 1966
Image of US PATENT 3,468,729

Abstract of the Disclosure

This invention relates to a method of making a semiconductor. A base semiconductor of "n" conductivity is selected and masked with an oxide coat on both sides of the semiconductor wafer. The oxide is removed from portions on opposite sides of the semiconductor. The oxide-removed surfaces do not overlap. The semiconductor is subjected to a diffusion environment wherein "p" and "n" or both simultaneously diffused into the wafer with the "p" impurity diffusing at a faster rate than the "n" impurity. The diffusion step produces a semiconductor material having four separate zones of differing conductivities in the semiconductor.
Figure descriptions: cover graphic

  • Figure 1 is a circuit diagram in accordance with the present invention.
  • Figure 2 illustrates the results of the first step of fabrication of the switching units of the present invention.
  • Figures 3 to 7, inclusive, illustrate subsequent steps of the method of fabrication of the present invention.
  • Figure 8 illustrates a pair of monolithic four-layer diodes made in accordance with the present invention.

 Citations [54]:
3,368,113 02/1968 Shaunfield 3,381,182 04/1968 Thornton
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