Abstract: A shielded junction field effect transistor (JFET) is described having gate trenches and shield trenches, the shield trenches being deeper and narrower than the gate trenches. The gate trenches may be fully aligned, partially aligned, or separated from the shield trenches.

Abstract: Disclosed inventions are directed to advanced high-voltage switches with improved performance characteristics, increased reliability, and better compatibility with conventional gate drivers. The inventions disclosed herein implement a hybrid switch, comprising a high-voltage normally-on SiC VJFET, controlled via a low-voltage Si MOSFET in a cascode (Baliga-pair) configuration. The SiC VJFET and Si MOSFET are integrated monolithically at a wafer level, with the Si MOSFET fabricated on the Si layer that is directly adjacent to a dielectric layer on top of the SiC VJFET. Methods of making and operating these switches are also provided.

Abstract: Disclosed herein are cascode switching circuits that include a normally-on semiconductor device, a normally-off semiconductor device, and a gate driver. The normally-on semiconductor device and said normally-off semiconductor device each has a gate terminal, a drain terminal and a source terminal. The gate driver has a first output and a second output, the first output of said gate driver is coupled to said gate terminal of said normally-on semiconductor device, the second output of said gate driver is coupled to said gate terminal of said normally-off semiconductor device, and the drain terminal of said normally-off semiconductor device is coupled to said source terminal of said normally-on semiconductor device so that a current path is formed through said normally-on semiconductor device and said normally-off semiconductor device. Methods of making and using such circuits, and other various aspects of such circuits are also disclosed.

Abstract: A heterostructure field effect transistor (HFET) gallium nitride (GaN) semiconductor power device comprises a hetero-junction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2DEG) layer. The power device further comprises a source electrode and a drain electrode disposed on two opposite sides of a gate electrode disposed on top of the hetero-junction structure for controlling a current flow between the source and drain electrodes in the 2DEG layer.

Abstract: The present disclosure describes a termination structure for a high voltage semiconductor transistor device. The termination structure is composed of at least two termination zones and an electrical disconnection between the body layer and the edge of the device. A first zone is configured to spread the electric field within the device. A second zone is configured to smoothly bring the electric field back up to the top surface of the device. The electrical disconnection prevents the device from short circuiting the edge of the device. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A transistor device includes a doped semiconductor substrate having one or more electrically insulated gate electrodes formed in trenches in the substrate. One or more body regions are formed in a top portion of the substrate proximate each gate trench. One or more source regions are formed in a self-aligned fashion in a top portion of the body regions proximate each gate trench. One or more thick insulator portions are formed over the gate electrodes on a top surface of the substrate with spaces between adjacent thick insulator portions. A metal is formed on top of the substrate over the thick insulator portions. The metal forms a self-aligned contact to the substrate through the spaces between the thick insulator portions. An integrated diode is formed under the self-aligned contact.

Abstract: A Schottky diode includes a Schottky barrier and a plurality of dopant regions disposed near the Schottky barrier as floating islands to function as PN junctions for preventing a leakage current generated from a reverse voltage. At least a trench opened in a semiconductor substrate with a Schottky barrier material disposed therein constitutes the Schottky barrier. The Schottky barrier material may also be disposed on sidewalls of the trench for constituting the Schottky barrier. The trench may be filled with the Schottky barrier material composed of Ti/TiN or a tungsten metal disposed therein for constituting the Schottky barrier. The trench is opened in a N-type semiconductor substrate and the dopant regions includes P-doped regions disposed under the trench constitute the floating islands. The P-doped floating islands may be formed as vertical arrays under the bottom of the trench.

Abstract: Semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In one embodiment, a semiconductor device is formed in a semiconductor layer on a semiconductor substrate of opposite conductivity type and having trenches formed therein where the trenches extend from the top surface to the bottom surface of the semiconductor layer. The semiconductor device includes a first epitaxial layer formed on sidewalls of the trenches where the first epitaxial layer is substantially charge balanced with adjacent semiconductor regions. In another embodiment, a semiconductor device is formed in a first semiconductor layer having trenches and mesas formed thereon where the trenches extend from the top surface to the bottom surface of the first semiconductor layer. The semiconductor device includes semiconductor regions formed on the bottom surface of the mesas of the first semiconductor layer.

Abstract: An oxide termination semiconductor device may comprise a plurality of gate trenches, a gate runner, and an insulator termination trench. The gate trenches are located in an active region. Each gate trench includes a conductive gate electrode. The insulator termination trench is located in a termination region that surrounds the active region. The insulator termination trench is filled with an insulator material to form an insulator termination for the semiconductor device. Source and body regions inside the active region are at source potential and source and body regions outside the isolation trench are at drain potential. The device can be made using a three-mask or four-mask process.

Abstract: A termination structure with multiple embedded potential spreading capacitive structures (TSMEC) and method are disclosed for terminating an adjacent trench MOSFET atop a bulk semiconductor layer (BSL) with bottom drain electrode. The BSL has a proximal bulk semiconductor wall (PBSW) supporting drain-source voltage (DSV) and separating TSMEC from trench MOSFET. The TSMEC has oxide-filled large deep trench (OFLDT) bounded by PBSW and a distal bulk semiconductor wall (DBSW). The OFLDT includes a large deep oxide trench into the BSL and embedded capacitive structures (EBCS) located inside the large deep oxide trench and between PBSW and DBSW for spatially spreading the DSV across them. In one embodiment, the EBCS contains interleaved conductive embedded polycrystalline semiconductor regions (EPSR) and oxide columns (OXC) of the OFLDT, a proximal EPSR next to PBSW is connected to an active upper source region and a distal EPSR next to DBSW is connected to the DBSW.

Abstract: This invention discloses a semiconductor power device. The trenched semiconductor power device includes a trenched gate, opened from a top surface of a semiconductor substrate, surrounded by a source region encompassed in a body region near the top surface above a drain region disposed on a bottom surface of a substrate. The semiconductor power device further includes an implanting-ion block disposed above the top surface on a mesa area next to the body region having a thickness substantially larger than 0.3 micron for blocking body implanting ions and source ions from entering into the substrate under the mesa area whereby masks for manufacturing the semiconductor power device can be reduced.

Abstract: This invention discloses a semiconductor power device disposed in a semiconductor substrate and the semiconductor substrate has a plurality of trenches. Each of the trenches is filled with a plurality of epitaxial layers of alternating conductivity types constituting nano tubes functioning as conducting channels stacked as layers extending along a sidewall direction with a “Gap Filler” layer filling a merging-gap between the nano tubes disposed substantially at a center of each of the trenches. The “Gap Filler” layer can be very lightly doped Silicon or grown and deposited dielectric layer. In an exemplary embodiment, the plurality of trenches are separated by pillar columns each having a width approximately half to one-third of a width of the trenches.

Abstract: This invention discloses configurations and methods to manufacture lateral power device including a super-junction structure with an avalanche clamp diode formed between the drain and the gate. The lateral super-junction structure reduces on-resistance, while the structural enhancements, including an avalanche clamping diode and an N buffer region, increase the breakdown voltage between substrate and drain and improve unclamped inductive switching (UIS) performance.

Abstract: This invention discloses a semiconductor power device formed in a semiconductor substrate comprises a highly doped region near a top surface of the semiconductor substrate on top of a lightly doped region. The semiconductor power device further comprises a body region, a source region and a gate disposed near the top surface of the semiconductor substrate and a drain disposed at a bottom surface of the semiconductor substrate. Source trenches are opened into the highly doped region filled with a conductive trench filling material in electrical contact with the source region near the top surface. A buried field ring regions is disposed below the source trenches and doped with dopants of opposite conductivity from the highly doped region. In an alternate embodiment, there are doped regions doped with a dopant of a same conductivity type of the buried field ring regions surrounding the sidewalls of the source trenches to function as a charge supply path.

Abstract: A hybrid semiconductor bipolar switch in which a normally-on high-voltage wide-bandgap semiconductor bipolar switch and a normally-off field effect transistor are connected in a cascode (Baliga-pair) configuration. The switch may be constructed as a stacked hybrid device where a discrete transistor is bonded on top of a bipolar switch. Power systems may use plural switches paired with anti-parallel diodes.

Abstract: Method for fabricating MOSFET integrated with Schottky diode (MOSFET/SKY) is disclosed. Gate trench is formed in an epitaxial layer overlaying semiconductor substrate, gate material is deposited therein. Body, source, dielectric regions are successively formed upon epitaxial layer and the gate trench. Top contact trench (TCT) is etched with vertical side walls defining Schottky diode cross-sectional width SDCW through dielectric and source region defining source-contact depth (SCD); and partially into body region by total body-contact depth (TBCD). A heavily-doped embedded body implant region (EBIR) of body-contact depth (BCD)<TBCD is created into side walls of TCT and beneath SCD. An embedded Shannon implant region (ESIR) is created into sub-contact trench zone (SCTZ) beneath TCT floor. A metal layer is formed in contact with ESIR, body and source region. The metal layer also fills TCT and covers dielectric region thus completing the MOSFET/SKY with only one-time etching of its TCT.

Abstract: A low capacitance transient voltage suppressor with reduced clamping voltage includes an n+ type substrate, a first epitaxial layer on the substrate, a buried layer formed within the first epitaxial layer, a second epitaxial layer on the first epitaxial layer, and an implant layer formed within the first epitaxial layer below the buried layer. The implant layer extends beyond the buried layer. A first trench is at an edge of the buried layer and an edge of the implant layer. A second trench is at another edge of the buried layer and extends into the implant layer. Each trench is lined with a dielectric layer. A set of source regions is formed within a top surface of the second epitaxial layer. The trenches and source regions alternate. A pair of implant regions is formed in the second epitaxial layer.

Abstract: A vertical conduction nitride-based Schottky diode is formed using an insulating substrate which was lifted off after the diode device is encapsulated on the front side with a wafer level molding compound. The wafer level molding compound provides structural support on the front side of the diode device to allow the insulating substrate to be lifted off so that a conductive layer can be formed on the backside of the diode device as the cathode electrode. A vertical conduction nitride-based Schottky diode is thus realized. In another embodiment, a protection circuit for a vertical GaN Schottky diode employs a silicon-based vertical PN junction diode connected in parallel to the GaN Schottky diode to divert reverse bias avalanche current.

Abstract: Transistor devices can be fabricated with an integrated diode using a self-alignment. The device includes a doped semiconductor substrate having one or more electrically insulated gate electrodes formed in trenches in the substrate. One or more body regions are formed in a top portion of the substrate proximate each gate trench. One or more source regions are formed in a self-aligned fashion in a top portion of the body regions proximate each gate trench. One or more thick insulator portions are formed over the gate electrodes on a top surface of the substrate with spaces between adjacent thick insulator portions. A metal is formed on top of the substrate over the thick insulator portions. The metal forms a self-aligned contact to the substrate through the spaces between the thick insulator portions. An integrated diode is formed under the self-aligned contact.

Abstract: Self-aligned charge balanced semiconductor devices and methods for forming such devices are disclosed. One or more planar gates are formed over a semiconductor substrate of a first conductivity type. One or more deep trenches are etched in the semiconductor self-aligned to the planar gates. The trenches are filled with a semiconductor material of a second conductivity type such that the deep trenches are charge balanced with the adjacent regions of the semiconductor substrate Source and body regions are formed by implanting dopants onto the filled trenches. This process can form self-aligned charge balanced devices with a cell pitch less than 12 microns.