Method of manufacturing double diffused transistor with base region parts of different depths

Claim 1

A METHOD OF MANUFACTURING A TRANSISTOR, COMPRISING PROVIDING A BODY HAVING AT LEAST A SEMICONDUCTIVE PART OF SILICON CONTAINING A SUBSTANTIALLY UNIFORM CONCENTRATION OF ONE TYPE OF CONDUCTIVITY-T-TYPE-DETERMINING IMPURITIES AND A PLANE SURFACE, FORMING ON THE SAID PLANE SURFACE AN ADHERENT PROTECTIVE INSULATION LAYER, PROVIDING A FIRST OPENING IN THE INSULATING LAYER TO FORM A FIRST EXPOSED LIMITED PORTION OF SAID PLANE SURFACE OF SAID BODY PART, DIFFUSING INTO SAID FIRST EXPOSED SURFACE PORTION SAID ONE TYPE IMPURITIES HAVING A RELATIVITY SLOW RATE OF DIFFUSION THEREIN AND IN QUANTITIES YIELDING A RELATIVELY HIGH DIFFUSED CONCENTRATION, THEREAFTER FORMING IN THE INSULATING LAYER A SECOND OPENING LARGER THAN THE FIRST OPENING TO FORM A SECOND EXPOSED LIMITED PORTION OF OF SAID PLANE SURFACE OF SAID BODY ART, AND DIFFUSING INTO SAID SECOND EXPOSED SURFACE PORTION CONDUCTIVITY-TYPE-DETERMINING IMPURITIES OF THE OPPOSITE TYPE HAVING A RELATIVELY HIGH RATE OF DIFFUSION IN THE BODY PART BUT IN QUANTITIES YIELDING A RELATIVELY LOWER DIFFUSED CONCENTRATION UNTIL THE OPPOSITE TYPE IMPURITIES PENETRATE INTO SAID BODY PART TO A GREATER DEPTH THAN SAID ONE TYPE DIFFUSED IMPURITIES FORMING A FIRST P-N JUNCTION WITH THE INITIAL BODY PART AND A SECOND P-N JUNCTION WITH THE BODY PART CONTAINING THE DIFFUSED ONE TYE IMPURITIES, SAID INSULATING LAYER BEING IMPERVIOUS TO BOTH DIFFUSED ONE TYPE AND OPPOSITE TYPE IMPURITIES, SAID SECOND EXPOSED PLANE SURFACE PORTION HAVING A GREATER SURFACE AREA THAN AND INCLUDING AND COMPLETELY SURROUNDING ON ALL SIDES SAID FIRST EXPOSED PLANE SURFACE PORTION, WHEREBY THE LATER DIFFUSED OPPOSITE TYPE IMPURITIES WHICH TRAVERSE A REGION OF SAID BODY PART WHICH CONTAINS THE ONE TYPE DIFFUSED IMPURITIES ARE SELECTIVELY RETARDED AND PENETRATE TO A LESSER DEPTH THAN THOSE WHICH TRAVERSE SURROUNDING REGIONS FREE OF SAID ONE TYPE DIFFUSED IMPURITIES AND THUS THE PART OF THE FIRST P-N JUNCTION UNDERNEATH THE FIRST EXPOSED PORTION LIES LESS DEEPLY IN THE BPDY THAN THE PARTS OF THE FIRST JUNCTION IN SURROUNDING PORTIONS.

Claim 2

A METHOD OF MANUFACTURING A TRANSISTOR, COMPRISING PROVIDING A BODY HAVING AT LEAST A SEMICONDUCTIVE PART OF SILICON CONTAINING A SUBSTANTIALLY UNIFORM CONCENTRATION OF ONE TYPE OF CONDUCTIVITY-T-TYPE-DETERMINING IMPURITIES AND A PLANE SURFACE, FORMING ON THE SAID PLANE SURFACE AN ADHERENT PROTECTIVE INSULATION LAYER, PROVIDING A FIRST OPENING IN THE INSULATING LAYER TO FORM A FIRST EXPOSED LIMITED PORTION OF SAID PLANE SURFACE OF SAID BODY PART, DIFFUSING INTO SAID FIRST EXPOSED SURFACE PORTION SAID ONE TYPE IMPURITIES HAVING A RELATIVITY SLOW RATE OF DIFFUSION THEREIN AND IN QUANTITIES YIELDING A RELATIVELY HIGH DIFFUSED CONCENTRATION, THEREAFTER FORMING IN THE INSULATING LAYER A SECOND OPENING LARGER THAN THE FIRST OPENING TO FORM A SECOND EXPOSED LIMITED PORTION OF OF SAID PLANE SURFACE OF SAID BODY ART, AND DIFFUSING INTO SAID SECOND EXPOSED SURFACE PORTION CONDUCTIVITY-TYPE-DETERMINING IMPURITIES OF THE OPPOSITE TYPE HAVING A RELATIVELY HIGH RATE OF DIFFUSION IN THE BODY PART BUT IN QUANTITIES YIELDING A RELATIVELY LOWER DIFFUSED CONCENTRATION UNTIL THE OPPOSITE TYPE IMPURITIES PENETRATE INTO SAID BODY PART TO A GREATER DEPTH THAN SAID ONE TYPE DIFFUSED IMPURITIES FORMING A FIRST P-N JUNCTION WITH THE INITIAL BODY PART AND A SECOND P-N JUNCTION WITH THE BODY PART CONTAINING THE DIFFUSED ONE TYE IMPURITIES, SAID INSULATING LAYER BEING IMPERVIOUS TO BOTH DIFFUSED ONE TYPE AND OPPOSITE TYPE IMPURITIES, SAID SECOND EXPOSED PLANE SURFACE PORTION HAVING A GREATER SURFACE AREA THAN AND INCLUDING AND COMPLETELY SURROUNDING ON ALL SIDES SAID FIRST EXPOSED PLANE SURFACE PORTION, WHEREBY THE LATER DIFFUSED OPPOSITE TYPE IMPURITIES WHICH TRAVERSE A REGION OF SAID BODY PART WHICH CONTAINS THE ONE TYPE DIFFUSED IMPURITIES ARE SELECTIVELY RETARDED AND PENETRATE TO A LESSER DEPTH THAN THOSE WHICH TRAVERSE SURROUNDING REGIONS FREE OF SAID ONE TYPE DIFFUSED IMPURITIES AND THUS THE PART OF THE FIRST P-N JUNCTION UNDERNEATH THE FIRST EXPOSED PORTION LIES LESS DEEPLY IN THE BPDY THAN THE PARTS OF THE FIRST JUNCTION IN SURROUNDING PORTIONS.