Method for making a high voltage semiconductor device

Claim 1

IN THE METHOD OF FABRICATING A SEMICONDUCTOR DEVICE WHICH HAS DESIRED REVERSE CURRENT AND BREAKDOWN VOLTAGE CHARACTERISTICS, (A) PROVIDING A SILICON SEMICONDUCTOR ELEMENT HAVING A FIRST REGION CONTAINING A FIRST IMPUIRTY WHICH IMPARTS A PREDETERMINED RESISTIVITY AND A PREDETERMINED CONDUCTIVITY TYPE TO SAID REGION, (B) FORMING A CHANNEL REGION AT THE TOP SURFACE OF SAID FIRST REGION WITH ONE FACE OF SAID CHANNEL REGION CONTIGUOUS WITH SAID FIRST REGION, SUCH CHANNEL REGION HAVING A SECOND IMPURITY THEREIN WHICH IMPARTS A CONDUCTIVITY TYPE OPPOSITE TO THAT OF SAID FIRST REGION AND A RESISTIVITY HIGHER THAN THAT OF SAID FIRST REGION, AND WHICH HAS A SEGREGATION COEFFICIENT SUCH THAT SAID SECOND IMPURITY SEGREGATES TO AT LEAST AS HIGH A CONCENTRATION IN A SILICON DIOXIDE INSULATING COATING THAT IS GROWN OVER THE ENTIRE TOP SURFACE OF SAID ELEMENT AS IN THE SILICON OF SAID CHANNEL REGION, WITH SAID CHANNEL REGION PREVENTING OXIDATION OF THE PORTION OF THE FIRST REGION CONTIGUOUS WITH SAID CHANNEL REGION DURING THE GROWTH OF AN INSULATING OXIDE COATING ON SAID TOP SURFACE TO MAINTAIN THE ORIGINAL RESISTIVITY OF SAID FIRST REGION, (C) GROWING AN INSULATING COATING OF SILICON DIOXIDE OVER THE ENTIRE TOP SURFACE OF SAID SEMICONDUCTOR ELEMENT IMMEDIATELY ABOVE SAID CHANNEL REGION, (D) FORMING AN OPENING IN SAID COATING DOWN TO THE SEMICONDUCTOR ELEMENT, (E) DIFFUSING THROUGH SAID OPENING AND SAID CHANNEL REGION INTO SAID FIRST REGION A SECOND REGION CONTAINING A THIRD IMPURITY AND EXTENDING UPWARDLY TO THE INSULATING COATING AND BEING OF OPPOSITE CONDUCTIVITY TYPE TO THAT OF SAID FIRST REGION, WITH A JUNCTION BEING FORMED AT THE INTERFACE OF SAID FIRST AND SECOND REGIONS, (F) GROWING AN INSULATING COATING OF SILICON DIOXIDE OVER THE ENTIRE TOP SURFACE OF SAID SEMICONDUCTOR ELEMENT, (G) FORMING AN OPENING IN SAID LATTER INSULATING COATING DOWN TO THE SEMICONCUDTOR ELEMENT, AND (H) FORMING A CHANNEL-INTERRUPTING REGION THROUGH SAID LATTER MEMTIONED OPEING WHICH EXTENDS DOWNWARDLY FROM SAID TOP SURFACE THROUGH SAID CHANNEL REGION INTO SAID FIRST REGION TO STRUCTURALLY BLOCK AND INTERRUPT SAID CHANNEL REGION OVER THE ENTIRE DEPTH THEREOF FROM SAID TOP SURFACE, WITH SAID CHANNEL-INTERRUPTING REGION SPACED LATERALLY AWAY AND SEPARATED FROM SAID SECOND REGION AND COMPLETELY SURROUNDING SAID SECOND REGION, AND BEING OF THE SAME CONDUCTIVITY TYPE AS THE FIRST REGION AND OF LOWER RESISTIVITY THAN THE SAME.