Zener diode structure

Claim 1

A temperature compensating buried zener diode device comprising: (a) a substrate of a first conductivity type semiconductor material; (b) a first layer of a second conductivity type semicondutor material disposed on said substrate and having a surface; (c) a second layer of highly doped second conductivity type semiconductor material intermediate a portion of said substrate and said first layer; (d) a first region of first conductivity type diposed within and in PN junction forming relation with said first layer and extending downwardly from said surface directly opposed but not in contact with one end of said second layer; (e) a second region of highly doped second conductivity type extending downwardly from said surface entirely within said first region and being in PN junction forming relation with said first region at an interface therebetween and forming a first zener breakdown junction at said interface; (f) a third region of highly doped first conductivity type in said first layer, said third region being in PN junction forming relation with said second region along a portion of said interface directly opposed said second layer thereby forming a second zener breakdown junction therebetween, said third region extending through both said first region and said first layer and into PN junction forming relation with said one end of said second layer thereby forming a third zener breakdown junction threebetween; and (g) a fourth region of second conductivity type in said first layer extending downwardly from said surface into electrical contact with another end of said second layer.