Integrated light-triggered and light-quenched static induction thyristor and making method thereof

An integrated light-triggered and light-quenched static induction thyristor assembly comprising:

• a buried-gate type of light-trigged static induction thyristor comprising:
• first conductivity type and regions formed on a first main surface of a high-resistivity substrate,
• gate regions having a first conductivity type and a high impurity density, partially buried into said substrate in the vicinity of a second main surface of said high-resistivity subtrate,
• a second conductivity type high-resistivity epitaxial layer formed in a way to bury said gate regions,
• a cathode region having a second conductivity type and a high impurify density, formed by diffusion into said epitaxial layer,
• cathode electrodes formed on said cathode regions and having windows for allowing triggering light pulses to penetrate therethrough,
• gate electrodes formed on said gate region,
• anode electrodes formed on said first main surface,
• a common drain region having said first conductivity type and an high impurity density and partially buried into said substrate in the vicinity of said second main surface of said substrate;
• first and second high-resistivity channel regions so formed as to bury said drain region and having said second conductivity type, said first and second channel regions isolated from each other;
• at least two first gate regions of said second conductivity type formed in said first channel region and at least two second gate regions of said second conductivity type formed in said second channel region;
• first source regions of said first conductivity type formed between adjacent ones of said first gate regions, and second source regions of said first conductivity type formed between adjacent ones of said second gate regions;
• isolation regions formed between said cathode regions and said first channel region, and having said second conductivity type and high impurity density;
• drain electrodes formed on said common drain region;
• first and second gate electrodes formed on said first and second gate regions respectively;
• and
• first and second source electrodes formed on said first and second source regions respectively;
• said first gate electrode on said first channel region and said second source electrode being connected to each other with a wire arranged through an insulating layer,
• a wire arranged through an insulating layer for connecting said gate electrodes and said first source electrodes;
• said isolation regions electrically isolating said buried-gate type of light trigged static induction thyristor from said darlington circuit, and arranged along the circumferences of said buried-gate type of static induction thyristor and said photodarlington circuit,
• wherein a first static induction phototransistor is formed by said common drain region, said first channel region, said first gate regions on said first channel region, and said first source region, and a second static induction phototransistor is formed by said common drain region, said second channel region, said second gate regions on said second channel region, and said second source region, said first and second static induction phototransistors forming a darlington circuit;
• wherein said isolation regions electrically isolate said light triggered static induction thyristor from said darlington circuit, and are arranged along the circumferences of said light-trigged static induction thyristor and said photodarlington circuit, and
• whereby said light-trigged and light-quenched static induction thyristor are turned on by said triggering light pulses irradiated through said windows formed in said cathode electrodes, and are turned off by quenching light pulses irradiated on said static induction phototransistors.