Patent ID: 6906356

Claim:
A switch, comprising: a device foundation, comprising: a first N+ substrate layer, a P− drift layer on said first N+ substrate layer, and a first electrode which contacts said first N+ substrate layer and provides a cathode connection for said device; a diode structure, comprising: said device foundation, a P+ layer on said P− drift layer, and a second electrode which contacts said P+ layer; a bipolar transistor (BJT) structure, comprising: said device foundation, a second N+ layer on said P− drift layer, and a third electrode which contacts said second N+ layer, said second and third electrodes connected together to provide an anode connection for said device; an insulated gate arranged in a trench configuration recessed into said device foundation between said diode and BJT structures, comprising: a layer of oxide in contact with said P+ layer, said P− drift layer, and said second N+ layer, said layer of oxide forming the walls and bottom of said trench, a conductive material within said trench which conducts a voltage applied to the top of said trench to said layer of oxide, and a fourth electrode which contacts said conductive material providing a gate connection for said device; and a shallow N+ region extending from the oxide bottom of said insulated gate into said P− drift layer and extending around the corners formed at the intersections of said gate's oxide side-walls and bottom; said device arranged such that a voltage applied across said anode and cathode connections sufficient to forward bias a first junction formed at the interface of said diode structure's P− drift and first N+ substrate layers causes electrons to be injected into the P− drift portion of said BJT, thereby providing a base drive current to said BJT sufficient to turn it on and enable current to flow from said anode connection to said cathode connection via said diode and BJT structures; and said device further arranged such that a voltage applied to said gate connection sufficient to reverse bias a second junction formed at the interface of said shallow N+ region and said P− drift layer forms depletion regions which, when said second junction is sufficiently reverse-biased, merge and form a potential barrier that blocks current flow through the diode and BJT structures and eliminates said base drive current such that said BJT and said switch are turned off.