Method for making a pnpn device by diffusing

Claim 1

A METHOD OF MAKING AN ALL-PLANAR DIFFUSED PNPN DEVICE COMPRISING THE STEPS OF OXIDIZING AN N-TYPE SILICON SLICE, REMOVING THE OXIDE IN SELECTED AREAS, DIFFUSING A P-TYPE IMPURITY INTO ONE FACE OF SAID SILICON SLICE AND INTO FIRST SELECTED AREAS ON THE FACE OPPOSITE SAID ONE FACE SO THAT SAID P-TYPE IMPURITY DIFFUSED IN SAID ONE FACE AND SAID FIRST SELECTED AREAS WILL EXTEND THROUGH SAID N-TYPE SILICON SLICE TO FORM CONTINUOUS P-TYPE REGIONS THROUGH SAID SLICE, GROWING AN OXIDE TO COVER SAID FIRST SELECTED DIFFUSED AREAS, REMOVING SAID OXIDE IN A SECOND SELECTED AREA ON THE FACE OPPOSITE SAID ONE FACE, DIFFUSING A P-TYPE IMPURITY INTO THE OPENING IN THE OXIDE TO FORM A SECOND P-TYPE REGION DISTINCT FROM SAID FIRST SELECTED DIFFUSED AREAS, GROWING AN OXIDE OVER SAID P-TYPE REGION, REMOVING SAID OXIDE IN A THIRD SELECTED AREA ON THE FACE OPPOSITE SAID ONE FACE, IDFFUSING AN N-TYPE IMPURITY TO FORM AN N-TYPE REGION IN SAID SECOND P-TYPE REGION, GROWING AN OXIDE OVER SAID N-TYPE REGION, REMOVING THE OXIDE EXPOSING A PORTION OF SAID SECND P-TYPE REGION AND SAID N-TYPE REGION AND EVAPORATING CONTACT MATERIAL TO ALLOY WITH SAID EXPOSED REGION.

Claim 2

A METHOD OF MAKING AN ALL-PLANAR DIFFUSED PNPN DEVICE COMPRISING THE STEPS OF OXIDIZING AN N-TYPE SILICON SLICE, REMOVING THE OXIDE IN SELECTED AREAS, DIFFUSING A P-TYPE IMPURITY INTO ONE FACE OF SAID SILICON SLICE AND INTO FIRST SELECTED AREAS ON THE FACE OPPOSITE SAID ONE FACE SO THAT SAID P-TYPE IMPURITY DIFFUSED IN SAID ONE FACE AND SAID FIRST SELECTED AREAS WILL EXTEND THROUGH SAID N-TYPE SILICON SLICE TO FORM CONTINUOUS P-TYPE REGIONS THROUGH SAID SLICE, GROWING AN OXIDE TO COVER SAID FIRST SELECTED DIFFUSED AREAS, REMOVING SAID OXIDE IN A SECOND SELECTED AREA ON THE FACE OPPOSITE SAID ONE FACE, DIFFUSING A P-TYPE IMPURITY INTO THE OPENING IN THE OXIDE TO FORM A SECOND P-TYPE REGION DISTINCT FROM SAID FIRST SELECTED DIFFUSED AREAS, GROWING AN OXIDE OVER SAID P-TYPE REGION, REMOVING SAID OXIDE IN A THIRD SELECTED AREA ON THE FACE OPPOSITE SAID ONE FACE, IDFFUSING AN N-TYPE IMPURITY TO FORM AN N-TYPE REGION IN SAID SECOND P-TYPE REGION, GROWING AN OXIDE OVER SAID N-TYPE REGION, REMOVING THE OXIDE EXPOSING A PORTION OF SAID SECND P-TYPE REGION AND SAID N-TYPE REGION AND EVAPORATING CONTACT MATERIAL TO ALLOY WITH SAID EXPOSED REGION.