Semiconductor switching element and process for producing the same

Claim 1

A PROCESS FOR PRODUCING A SEMICONDUCTOR SWITCHING ELEMENT WHICH COMPRISES: FORMING A FIRST SEMICONDUCTOR DOMAIN OF A FIRST CONDUCTIVITY TYPE ON ONE SURFACE OF A BASE BODY SEMICONDUCTOR WHOSE CONDUCTIVITY TYPE IS SELECTED FROM THE GROUP CONSISTING OF SAID FIRST CONDUCTIVITY TYPE, THE INTRINSIC CONDUCTIVITY TYPE, AND A SECOND CONDUCTIVITY TYPE; SAID BASE BODY SEMICONDUCTOR HAVING A LOWER ACTIVE IMPURITY CONCENTRATION THAN THAT OF SAID FIRST SEMICONDUCTOR DOMAIN; MELTING AGAINST ANOTHER SURFACE OF SAID BASE BODY SEMICONDUCTOR AN ALLOY CONTAINING A FIRST ACTIVE IMPURITY WHICH HAS A FLUCTUATING EFFECTIVE SEGREGATION COEFFICIENT IN THE RECRYSTALLIZATION GROWTH RATE OF THE BASE BODY SEMICONDUCTOR, AND WHICH FIRST IMPURITY IMPARTS THE SECOND CONDUCTIVITY TYPE WITH RESPECT TO THE BASE BODY SEMICONDUCTOR; SAID ALLOY ALSO CONTAINING A SECOND ACTIVE IMPURITY WHICH HAS A SMALLER FLUCTUATION OF EFFECTIVE SEGREGATION COEFFICIENT THAN SAID FIRST ACTIVE IMPURITY, AND WHICH SECOND IMPURITY IMPARTS THE FIRST CONDUCTIVITY TYPE WITH RESPECT TO SAID BASE BODY SEMICONDUCTOR; THEREAFTER COOLING THE RESULTING MOLTEN ALLOY AT SUCH A RATE, RELATIVE TO THE RESPECTIVE PROPORTIONS OF SAID ACTIVE IMPURITIES AND THEIR SEGREGATION-COEFFICIENT FLUCTUATION RATES, AS TO PRODUCE RECRYSTALLIZATION OF THE SEMICONDUCTOR DOMAIN OF THE FIRST CONDUCTIVITY TYPE AND OF HIGH IMPURITY CONCENTRATION NEXT TO THE SAID BASE BODY SEMICONDUCTOR, FOLLOWED BY RECRYSTALLIZATION OF THE SEMICONDUCTOR DOMAIN OF THE SECOND CONDUCTIVITY TYPE AND OF LOWER EFFECTIVE IMPURITY CONCENTRATION.