Bi-directional trench power switches. At least one example is a semiconductor device comprising: an upper base region associated with a first side of a substrate of semiconductor material; an upper-CE trench defined on the first side, the upper-CE trench defines a proximal opening at the first side and a distal end within the substrate; an upper collector-emitter region disposed at the distal end of the upper-CE trench; a lower base region associated with a second side of substrate; and a lower collector-emitter region associated with the second side.

A bidirectional Metal-Oxide-Semiconductor (MOS) device, including a P-type substrate, and an active region. The active region includes a drift region, a first MOS structure and a second MOS structure; the first MOS structure includes a first P-type body region, a first P+ contact region, a first N+ source region, a first metal electrode, and a first gate structure; the second MOS structure includes a second P-type body region, a second P+ contact region, a second N+ source region, a second metal electrode, and a second gate structure; and the drift region includes a dielectric slot, a first N-type layer, a second N-type layer, and an N-type region. The active region is disposed on the upper surface of the P-type substrate. The first MOS structure and the second MOS structure are symmetrically disposed on two ends of the upper layer of the drift region.

Three optimizations are provided for B-TRAN devices which include field plate trenches: 1) the trench dielectric thickness is large enough to withstand the base-to-emitter voltage, but thin enough to provide good electrical coupling between the poly field plate and the adjacent p-type silicon; 2) the base contact width is small enough to provide an acceptably low reverse base contact region pinch-off voltage, but large enough to avoid degradation of both base resistance; and 3) the emitter width is small enough to keep an acceptably high current density at the emitter's center.

A TRIAC features first and second main-terminal contacts, and a gate terminal contact, with multiple semiconductor regions stacked along a first-axis and extending laterally along an intersecting second-axis that defines first, second, and middle regions. The semiconductor regions include a third N-type region overlying the second main-terminal contact, a second P-type region overlying the second main-terminal contact, a second N-type region overlying the second P-type region, a first P-type region overlying the second N-type region, a first N-type region partially overlying the first P-type region, a fourth N-type region partially overlying the first P-type region, and a fifth N-type region partially overlying the first P-type region. The first main-terminal contact is partly on the first N-type region in the first region and on the first P-type region in the second region, while the gate terminal contact is partly on both the first P-type region and the fourth N-type region.