Semiconductor switching device

Claim 2

A semiconductor switching device comprising: a first emitter layer of a first type conductivity, a first base layer of a second type conductivity disposed on said first emitter layer, a second base layer of said first type conductivity disposed on said first base layer, a second emitter layer of said second type conductivity disposed in a surface adjacent portion of said second base layer, an auxiliary emitter layer of said second type conductivity disposed in a surface adjacent portion of said second base layer and separated from said second emitter layer, an anode electrode disposed in ohmic contact with said first emitter layer, a cathode electrode disposed in ohmic contact with said second emitter layer, a first auxiliary gate electrode disposed in ohmic contact with the both said auxiliary emitter layer and one portion of said second base layer to bridge them, a second auxIliary gate electrode disposed in ohmic contact with said second base layer and interposed between said cathode electrode and said first auxiliary gate electrode, a gate electrode disposed in ohmic contact with said second base layer opposed to said first auxiliary gate electrode, said gate electrode being located on said second base layer on that side of said first auxiliary gate electrode remote from said second auxiliary gate electrode, and circuit means for applying a gate signal said gate electrode to turn the device on and for applying to said second auxiliary gate electrode a gate signal opposite in polarity to the firstmentioned gate signal to turn the device off.

Claim 3

A semiconductor switching device as claimed in claim 1 wherein said first auxiliary gate electrode bridges said auxiliary emitter layer and that portion of said second base layer near to said cathode electrode.

Claim 4

A semiconductor switching device as claimed in claim 1 wherein said second auxiliary gate electrode is positioned with respect to said first auxiliary gate electrode at a predetermined spacing so that that portion of the surface of said second base layer disposed between said first and second auxiliary gate electrodes has formed thereon a resistance having a magnitude sufficient to prevent a P-N junction formed between said auxiliary emitter layer and said second base layer from being forwardly biased.

Claim 5

A semiconductor switching device as claimed in claim 1 wherein a semiconductor diode is connected across said second auxiliary gate electrode and said gate electrode so that a forward current flows from said second auxiliary gate electrode toward said gate electrode, therethrough.

Claim 6

A semiconductor switching device as claimed in claim 1 wherein gold is diffused at least said first base layer and said second base layer.

Claim 7

A semiconductor switching device as claimed in claim 1 wherein said gate electrode is located on the central portion of said second base layer, and surrounded by said first auxiliary gate electrode, and said second auxiliary gate electrode surrounds said first auxiliary gate electrode and includes a plurality of protrusions radially outwardly directed and extending into corresponding indentations in said first auxiliary gate electrode with a space therebetween.

Claim 8

A semiconductor switching device as claimed in claim 1 wherein said first base layer includes one portion electrically connected to said anode electrode and said second base layer includes one portion electrically connected to said cathode electrode whereby the device forms a reverse conducting thyristor.

Claim 9

A semicondutor switching device comprising a first emitter layer of a first type conductivity, a first base layer of a second type conductivity disposed on said first emitter layer, a second base layer of said first type conductivity disposed on said first base layer, a second emitter layer of said second type conductivity disposed in a surface adjacent portion of said second base layer, an auxiliary emitter layer of said second type conductivity disposed in a surface adjacent portion of said second base layer and separated from said second emitter layer, an anode electrode disposed in ohmic contact with said first emitter layer, a cathode electrode disposed in ohmic contact with said second emitter layer, an auxiliary emitter electrode disposed in ohmic contact with said auxiliary emitter layer, a first auxiliary gate electrode disposed in ohmic contact with said second base layer and between said cathode electrode and said auxiliary emitter electrode, said first auxiliary gate electrode being connected to said auxiliary emitter electrode, a second auxiliary gate electrode disposed in ohmic contact with said second base layer and between said cathode electrode and said first auxiliary gate electrode, a gate electrode disposed in ohmic contact with said second base layer and on that side of said auxiliary emitter electrode remote from said first auxiliary gate electrode, and circuiT means for applying a gate signal to said gate electrode to turn the device on and for applying to said second auxiliary gate electrode a gate signal opposite in polarity to the firstmentioned gate signal to turn the device off.

Claim 10

A semicondutor switching device comprising a first emitter layer of a first type conductivity, a first base layer of a second type conductivity disposed on said first emitter layer, a second base layer of said first type conductivity disposed on said first base layer, a second emitter layer of said second type conductivity disposed in a surface adjacent portion of said second base layer, an auxiliary emitter layer of said second type conductivity disposed in a surface adjacent portion of said second base layer and separated from said second emitter layer, an anode electrode disposed in ohmic contact with said first emitter layer, a cathode electrode disposed in ohmic contact with said second emitter layer, an auxiliary emitter electrode disposed in ohmic contact with said auxiliary emitter layer, a first auxiliary gate electrode disposed in ohmic contact with said second base layer and between said cathode electrode and said auxiliary emitter electrode, said first auxiliary gate electrode being connected to said auxiliary emitter electrode, a second auxiliary gate electrode disposed in ohmic contact with said second base layer and between said cathode electrode and said first auxiliary gate electrode, a gate electrode disposed in ohmic contact with said second base layer and on that side of said auxiliary emitter electrode remote from said first auxiliary gate electrode, and circuiT means for applying a gate signal to said gate electrode to turn the device on and for applying to said second auxiliary gate electrode a gate signal opposite in polarity to the firstmentioned gate signal to turn the device off.

Claim 11

A semiconductor switching device as claimed in claim 8 wherein a semiconductor diode is connected across said second auxiliary gate electrode and said gate electrode so that a forward current flows from said second auxiliary gate electrode toward said gate electrode therethrough.