A gate-controlled thyristor, comprising: an n-type emitter region, overlying a p-type base region, which itself overlies an n-type base region, which in turn overlies a p-type emitter region, wherein a doping level of the p-type emitter region is greater than a doping level of the p-type base region, wherein the n-type emitter region, the p-type base region, and the n-type base region form an NPN transistor, and wherein the p-type emitter region, the n-type base region, and the p-type base region form a PNP transistor; an anode terminal connected to the p-type emitter region and a cathode terminal connected to the n-type emitter region; insulated gate electrodes lying in gate trenches which extend through the n-type emitter region and down into, but not through, said p-type base region; wherein the NPN transistor current gain defined by the combination of said n-type emitter region with said p-type base region and said n-type base region, multiplied by the PNP transistor current gain defined by the combination of said p-type emitter region with said n-type base region and said p-type base region, is less than one when a voltage less than a threshold voltage is applied to said insulated gate electrodes; wherein, when said insulated gate electrodes have been driven sufficiently positive, with respect to a potential of the p-type base region, to invert portions of said p-type base region at the sidewalls and the bottom of said gate trenches, the NPN transistor current gain defined by the combination of an induced population of electrons at the bottom of said trenches with said p-type base region and said n-type base region, multiplied by the PNP transistor current gain defined by the combination of said p-type emitter region with said n-type base region and said p-type base region, is greater than one; whereby, when a voltage applied to said gate electrodes is sufficiently positive to invert said p-base region, current will flow from the anode terminal to the cathode terminal under forward bias; and when a voltage applied to said insulated gate electrodes is at the same voltage potential as the p-type base region, the gate electrodes are not driven sufficiently positive to invert said p-base region, and current from said anode terminal to said cathode terminal will be interrupted. an n-type emitter region, overlying a p-type base region, which itself overlies an n-type base region, which in turn overlies a p-type emitter region, wherein a doping level of the p-type emitter region is greater than a doping level of the p-type base region, wherein the n-type emitter region, the p-type base region, and the n-type base region form an NPN transistor, and wherein the p-type emitter region, the n-type base region, and the p-type base region form a PNP transistor; an anode terminal connected to the p-type emitter region and a cathode terminal connected to the n-type emitter region; insulated gate electrodes lying in gate trenches which extend through the n-type emitter region and down into, but not through, said p-type base region; wherein the NPN transistor current gain defined by the combination of said n-type emitter region with said p-type base region and said n-type base region, multiplied by the PNP transistor current gain defined by the combination of said p-type emitter region with said n-type base region and said p-type base region, is less than one when a voltage less than a threshold voltage is applied to said insulated gate electrodes; wherein, when said insulated gate electrodes have been driven sufficiently positive, with respect to a potential of the p-type base region, to invert portions of said p-type base region at the sidewalls and the bottom of said gate trenches, the NPN transistor current gain defined by the combination of an induced population of electrons at the bottom of said trenches with said p-type base region and said n-type base region, multiplied by the PNP transistor current gain defined by the combination of said p-type emitter region with said n-type base region and said p-type base region, is greater than one; whereby, when a voltage applied to said gate electrodes is sufficiently positive to invert said p-base region, current will flow from the anode terminal to the cathode terminal under forward bias; and when a voltage applied to said insulated gate electrodes is at the same voltage potential as the p-type base region, the gate electrodes are not driven sufficiently positive to invert said p-base region, and current from said anode terminal to said cathode terminal will be interrupted.