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 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