Abstract of the Disclosure

A protective element that turns on at a punch-through voltage less than the oxide breakdown voltage is connected to the gate electrode of an active MOS device to avoid destructive breakdown of the oxide layer.

• Figure 1 is a a partial cross sectional view of a protected MOS transistor in accordance with the present invention.
• Figures 2 and 3 are graphs of data useful in the design of protected MOS transistors in accordance with this invention.
• Figure 4 is the approximate equivalent circuit of the structure of Figure 1.
• Figure 5 is a partial sectional view of an alternative embodiments of the the present invention.
• Figure 6 illustrates another form of the invention.

 Citations [54]:
  
3,230,429  01/1966  Stehney
3,356,858  12/1967  Wanlass
3,264,493  08/1966  Price
3,395,290  07/1968  Farina
3,272,989  09/1966  Sekely
3,403,270  09/1968  Pace
3,289,093  11/1966  Wanlass
3,407,339  10/1968  Booher
3,340,598  09/1967  Hatcher