Abstract: This invention discloses a DMOS power device supported on a substrate of a first conductivity type functioning as a drain. The DMOS power device includes a polysilicon-over-double-gate-oxide gate disposed on the substrate includes a polysilicon layer disposed over a double-gate-oxide structure having a central thick-gate-oxide segment surrounded by a thin-gate-oxide layer with a thickness of about one-fourth to one-half of a thickness of the thick-gate-oxide segment. The DMOS power device further includes a body region of a second conductivity type disposed in the substrate underneath the thin-gate-oxide layer around edges of the central thick-gate-oxide segment the body region extending out laterally to a neighboring device circuit element. The DMOS power device further includes a source region of the first conductivity type disposed in the substrate encompassed in the body region having a portion extending laterally underneath the thin-gate-oxide layer.

Abstract: A new transistor cell is disclosed in this invention which is formed in a semiconductor substrate with a drain region of a first conductivity type formed at a bottom surface of the substrate. The DMOS cell includes a polysilicon layer constituting a gate supported on a top surface of the substrate, the gate surrounding and defining an outer boundary of the transistor cell having a removed polysilicon opening disposed substantially in a central portion of the cell. The DMOS cell further includes a source region of the first conductivity disposed in the substrate near edges of the removed polysilicon opening with a portion extends underneath the gate. The DMOS cell further includes a body region of a second conductivity type disposed in the substrate occupying an entire region under the removed polysilicon opening thus encompassing the source region and having a portion extends underneath the gate.

Abstract: The invention discloses method for fabricating a MOSFET on a substrate to improve device ruggedness.

Abstract: This invention discloses a MOSFET device in a semiconductor chip with a top surface and a bottom surface. The MOSFET device includes a drain region, doped with impurities of a first conductivity type, formed in the semiconductor chip near the bottom surface. The MOSFET device further includes a vertical pn-junction region, which includes a lower-outer body region, doped with impurities of a second conductivity type, formed on top of the drain region. The pn-junction region further includes a source region, doped with impurities of the first conductivity type, formed on top of the lower-outer body region wherein the lower-outer body region defining a channel region extending from the source region to the drain region near the top surface. The MOSFET device further includes a gate formed on top of the channel region on the top surface. The gate includes a thin insulative bottom layer for insulating from the channel region.

Abstract: This invention discloses a MOSFET device which includes a plurality of vertical cells each includes a source, a drain, and a channel for conducting source-to-drain current therethrough. Each of the vertical cells is surrounded by a polysilicon layer acting as a gate for controlling the source-to-drain current through the channel. The MOSFET device further include a plurality of doping trenches filled with trench-filling materials, The MOSFET device further includes a plurality of deep-doped regions disposed underneath the doping trenches wherein the deep-doped region extends downwardly to a depth which is substantially a sum of an implant depth of the deep-doped region and a vertical diffusion depth below a bottom of the doping trenches.

Abstract: The present invention discloses a power transistor disposed on a substrate. The power device includes a core cell area comprising a plurality of power transistor cells each having drain and a source. Each of the power transistor cells further having a polycrystalline silicon gate formed on the substrate as part of a polycrystalline silicon gate layer overlaying the substrate. The polycrystalline silicon gate layer includes a plurality of polycrystalline gate-layer-extension extending to gate contact areas for forming gate contacts with a contact metal disposed thereon. The power transistor further includes a plurality of contact-metal-resistant pad each includes a thick oxide pad disposed below the gate contact areas underneath the polycrystalline gate layer extension whereby the contact-metal resistant pads resists the contact metal from penetrating therethrough and short to the substrate disposed thereunder.

Abstract: Improved power MOSFET structure, and fabrication process are disclosed in this invention to achieve higher breakdown voltage and improved device ruggedness. The power transistor includes a core cell area which includes a plurality of power transistor cells and a termination area. The power transistor further includes an outer pickup guarding ring, disposed in the termination area guarding the core cell area, for picking up free charged-particles generated in the termination area for preventing the free charged particles from entering the core cell area. In another preferred embodiment, the power transistor further includes an inner pickup guarding fence and blocks, disposed between the termination area and the core cell area for picking up free charged-particles not yet picked up by the outer pickup guarding ring for preventing the free charged particles from entering the core cell area.

Abstract: Improved power MOSFET structure, and fabrication process are disclosed in this invention to achieve cost savings by simplified device structure and fabrication processes, and also by reducing the required die size. Specifically, in a novel MOSFET device, insulation of mobile ions are achieved by extending the poly gate and metal contacts such that the passivation layer is no longer required and the fabrication process is simplified such that the MOSFET device can be manufactured at a lower price. Furthermore, in another MOSFET device, the gate runner is used to replace the field plate such that the requirement of a field plate as that in a conventional MOSFET device is also eliminated and, by reducing the die size, the cost of manufacture is further reduced.

Abstract: The present invention discloses a power transistor cell supported on a semiconductor substrate with a top surface and a bottom surface. The power transistor cell includes a drain region, doped with impurities of a first conductivity type, formed at the bottom surface. The power transistor cell further includes a polysilicon gate layer overlaying the top surface includes a polysilicon opening disposed substantially in a central portion of the transistor cell with a remaining portion of the polysilicon layer constituting a gate and defining an outer boundary for the transistor cell wherein the polysilicon opening and the outer boundary defined by the gate for the transistor cell constituting substantially non-orthogonal parallelograms. The power transistor further includes a source region, doped with the first conductivity type, disposed in the substrate underneath and around an outer edge of the source opening with a small portion extends underneath the gate.

Abstract: Improved power MOSFET structure, and fabrication process are disclosed in this invention to achieve a low threshold voltage. The improved MOSFET device is formed in a semiconductor substrate with a drain region formed near a bottom surface of the substrate supporting a plurality of double-diffused vertical cells thereon wherein each of the vertical cells including a pn-junction having a body region surrounding a source region and each of the vertical cell further including a gate above the pn-junction. Each of the vertical cells further includes a source-dopant segregation reduction layer for reducing a surface segregation between the source region and an oxide layer underneath the gate whereby the body surface peak dopant concentration near an interface between the source region and the body region is reduced for reducing a threshold voltage of the MOSFET device.

Abstract: A new DMOS fabrication process is disclosed.