The present disclosure relates to semiconductor structures and, more particularly, to a symmetric tunnel field effect transistor and methods of manufacture. The structure includes a gate structure including a source region and a drain region both of which comprise a doped VO.sub.2 region.

The present disclosure relates to semiconductor structures and, more particularly, to a symmetric tunnel field effect transistor and methods of manufacture. The structure includes a gate structure including a source region and a drain region both of which comprise a doped VO.sub.2 region.

Depositing gallium nitride and carbon (GaN:C) (e.g., in the form of composite layers) when forming a gallium nitride drain of a transistor provides a buffer between the gallium nitride of the drain and silicon of a substrate in which the drain is formed. As a result, gaps and other defects caused by lattice mismatch are reduced, which improves electrical performance of the drain. Additionally, current leakage into the substrate is reduced, which further improves electrical performance of the drain. Additionally, or alternatively, implanting silicon in an aluminum nitride (AlN) liner for a gallium nitride drain reduces contact resistance at an interface between the gallium nitride and the silicon. As a result, electrical performance of the transistor is improved.

A diode string having a plurality of diodes for ESD protection of a CMOS IC device comprises a first diode and a last diode in the diode string, wherein the first diode and the last diode are both formed on a bottom layer in a silicon substrate, and remaining diodes in the diode string. The remaining diodes are formed on a top layer placed on top of the bottom layer. The diode string further comprises a plurality of conductive lines that connect the first diode and the last diode on the bottom layer sequentially with the remaining diodes on the top layer to form a three dimensional (3D) structure of the diode string.

A two-transistor memory cell based upon a thyristor for an SRAM integrated circuit is described together with a process for fabricating it. The memory cell can be implemented in different combinations of MOS and bipolar select transistors, or without select transistors, with thyristors in a semiconductor substrate with shallow trench isolation. Standard CMOS process technology can be used to manufacture the SRAM.

A semiconductor device and manufacturing method achieve miniaturization, prevent rise in threshold voltage and on-state voltage, and prevent decrease in breakdown resistance. N.sup.+-type emitter region and p.sup.++-type contact region are repeatedly alternately disposed in a first direction in which a trench extends in stripe form in a mesa portion sandwiched between trench gates. P.sup.+-type region covers an end portion on lower side of junction interface between n.sup.+-type emitter region and p.sup.++-type contact region. Formation of trench gate structure is such that n.sup.+-type emitter region is selectively formed at predetermined intervals in the first direction in the mesa portion by first ion implantation. P.sup.+-type region is formed less deeply than n.sup.+-type emitter region in the entire mesa portion by second ion implantation. The p.sup.++-type contact region is selectively formed inside the p+-type region by third ion implantation. N.sup.+-type emitter region and p.sup.++-type contact region are diffused and brought into contact.

The invention provides a semiconductor device. The semiconductor device includes a buried oxide layer disposed on a substrate. A semiconductor layer having a first conduction type is disposed on the buried oxide layer. A first well doped region having a second conduction type is disposed in the semiconductor layer. A cathode doped region having the second conduction type is disposed in the first well doped region. A first anode doped region having the first conduction type is disposed in the first well doped region, separated from the cathode doped region. A first distance from a bottom boundary of the first anode doped region to a top surface of the semiconductor layer is greater than a second distance from the bottom boundary to an interface between the semiconductor layer and the buried oxide layer.

A semiconductor device includes a transistor that has: a drift region of a first conductivity type in a semiconductor substrate having a first main surface; a body region of a second conductivity type between the drift region and the first main surface; a plurality of trenches in the first main surface and patterning the semiconductor substrate into a plurality of mesas including a first mesa and a plurality of dummy mesas, the plurality of trenches including an active trench and a plurality of dummy trenches arranged in a row; a gate electrode arranged in the active trench; and a source region of the first conductivity type in the first mesa. The first mesa is arranged adjacent to the active trench. A dummy mesa is arranged between each adjacent pair of the dummy trenches. The dummy mesas do not carry load current during an on-state of the transistor.

A method for forming a semiconductor device includes forming at least one graphene layer on a surface of a semiconductor substrate. The method further includes forming a silicon carbide layer on the at least one graphene layer.

A semiconductor device includes a transistor that has: a drift region of a first conductivity type in a semiconductor substrate having a first main surface; a body region of a second conductivity type between the drift region and the first main surface; trenches in the first main surface and patterning the semiconductor substrate into mesas including a first mesa and a dummy mesa, the trenches including an active trench and a dummy trenches arranged in a row; a gate electrode arranged in the active trench; and a source region of the first conductivity type in the first mesa. The first mesa is arranged adjacent to the active trench. The dummy mesa is arranged between each adjacent pair of the dummy trenches and does not include a source region.