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Hong Chang, Cupertino US

Hong Chang, Cupertino, CA US

Patent application numberDescriptionPublished
20090148995Processes for manufacturing MOSFET devices with excessive round-hole shielded gate trench (SGT) - This invention discloses an improved method for manufacturing a trenched metal oxide semiconductor field effect transistor (MOSFET) device. The method includes a step of opening a trench in substrate and covering trench walls of the trench with a linen layer followed by removing a portion of the linen layer from a bottom portion of the trench. The method further includes a step of opening a round hole by applying an isotropic substrate etch on the bottom portion of the trench with the round hole extending laterally from the trench walls. The method further includes a step of filling the trench and the round hole at the bottom of the trench with a gate material followed by applying a time etch to removed the gate material from a top portion of the trench whereby the gate material only filling the round hole up to a lateral expansion point of the round hole.06-11-2009
20100084707Polysilicon control etch-back indicator - This invention discloses a semiconductor wafer for manufacturing electronic circuit thereon. The semiconductor substrate further includes an etch-back indicator that includes trenches of different sizes having polysilicon filled in the trenches and then completely removed from some of the trenches of greater planar trench dimensions and the polysilicon still remaining in a bottom portion in some of the trenches having smaller planar trench dimensions.04-08-2010
20100099230Method to manufacture split gate with high density plasma oxide layer as inter-polysilicon insulation layer - This invention discloses a method of manufacturing a trenched semiconductor power device with split gate filling a trench opened in a semiconductor substrate wherein the split gate is separated by an inter-poly insulation layer disposed between a top and a bottom gate segments. The method further includes a step of forming the inter-poly layer by applying a RTP process after a HDP oxide deposition process to bring an etch rate of the HDP oxide layer close to an etch rate of a thermal oxide.04-22-2010
20100105182Shallow source MOSFET - Fabricating a semiconductor device includes forming a hard mask on a substrate having a top substrate surface, forming a trench in the substrate through the hard mask, depositing gate material in the trench, where the amount of gate material deposited in the trench extends beyond the top substrate surface, and removing the hard mask to leave a gate having a gate top surface that extends substantially above the top substrate surface at least in center region of the trench opening, the gate having a vertical edge that includes an extended portion, the extended portion extending above the trench opening and being substantially aligned with the trench wall. It further includes implanting a body, implanting a plurality of source regions embedded in the body, forming a plurality of spacers that insulate the source regions from the gate, the plurality of spacers being situated immediately adjacent to the gate and immediately adjacent to respective ones of the plurality of source regions, wherein the plurality of spacers do not substantially extend into the trench and do not substantially extend over the trench, disposing a dielectric layer over the source, the spacers, the gate, and at least a portion of the body, forming a contact opening, and disposing metal to form a contact with the body at the contact opening.04-29-2010
20100190307HIGH DENSITY TRENCH MOSFET WITH SINGLE MASK PRE-DEFINED GATE AND CONTACT TRENCHES - Trench gate MOSFET devices may be formed using a single mask to define gate trenches and body contact trenches. A hard mask is formed on a surface of a semiconductor substrate. A trench mask is applied on the hard mask to predefine a body contact trench and a gate trench. These predefined trenches are simultaneously etched into the substrate to a first predetermined depth. A gate trench mask is next applied on top of the hard mask. The gate trench mask covers the body contact trenches and has openings at the gate trenches that are wider than those trenches. The gate trench, but not the body contact trench, is etched to a second predetermined depth. Conductive material of a first kind may fill the gate trench to form a gate. Conductive material of a second kind may fill the body contact trench to form a body contact.07-29-2010
20100291744HIGH DENSITY TRENCH MOSFET WITH SINGLE MASK PRE-DEFINED GATE AND CONTACT TRENCHES - Trench gate MOSFET devices may be formed using a single mask to define gate trenches and body contact trenches. A hard mask is formed on a surface of a semiconductor substrate. A trench mask is applied on the hard mask to predefine a body contact trench and a gate trench. These predefined trenches are simultaneously etched into the substrate to a first predetermined depth. A gate trench mask is next applied on top of the hard mask. The gate trench mask covers the body contact trenches and has openings at the gate trenches. The gate trench, but not the body contact trench, is etched to a second predetermined depth. Conductive material of a first kind may fill the gate trench to form a gate. Conductive material of a second kind may fill the body contact trench to form a body contact.11-18-2010
20100314659Nanotube Semiconductor Devices - A semiconductor device includes a first semiconductor layer and a second semiconductor layer of opposite conductivity type, a first epitaxial layer of the first conductivity type formed on sidewalls of the trenches, and a second epitaxial layer of the second conductivity type formed on the first epitaxial layer where the second epitaxial layer is electrically connected to the second semiconductor layer. The first epitaxial layer and the second epitaxial layer form parallel doped regions along the sidewalls of the trenches, each having uniform doping concentration. The second epitaxial layer has a first thickness and a first doping concentration and the first epitaxial layer and a mesa of the first semiconductor layer together having a second thickness and a second average doping concentration where the first and second thicknesses and the first doping concentration and second average doping concentrations are selected to achieve charge balance in operation.12-16-2010
20100317158Method for Forming Nanotube Semiconductor Devices - A method for forming a semiconductor device includes forming a nanotube region using a thin epitaxial layer formed on the sidewall of a trench in the semiconductor body. The thin epitaxial layer has uniform doping concentration. In another embodiment, a first thin epitaxial layer of the same conductivity type as the semiconductor body is formed on the sidewall of a trench in the semiconductor body and a second thin epitaxial layer of the opposite conductivity type is formed on the first epitaxial layer. The first and second epitaxial layers have uniform doping concentration. The thickness and doping concentrations of the first and second epitaxial layers and the semiconductor body are selected to achieve charge balance. In one embodiment, the semiconductor body is a lightly doped P-type substrate. A vertical trench MOSFET, an IGBT, a Schottky diode and a P-N junction diode can be formed using the same N-Epi/P-Epi nanotube structure.12-16-2010
20110037120Shielded gate trench MOSFET device and fabrication - A semiconductor device embodiment includes a substrate, an active gate trench in the substrate, and an asymmetric trench in the substrate. The asymmetric trench has a first trench wall and a second trench wall, the first trench wall is lined with oxide having a first thickness, and the second trench wall is lined with oxide having a second thickness that is different from the first thickness. Another semiconductor device embodiment includes a substrate, an active gate trench in the substrate; and a source polysilicon pickup trench in the substrate. The source polysilicon pickup trench includes a polysilicon electrode, and top surface of the polysilicon electrode is below a bottom of a body region. Another semiconductor device includes a substrate, an active gate trench in the substrate, the active gate trench has a first top gate electrode and a first bottom source electrode, and a gate runner trench comprising a second top gate electrode and a second bottom source electrode. The second top gate electrode is narrower than the second bottom source electrode.02-17-2011
20110039383Shielded gate trench MOSFET device and fabrication - A method for fabricating a semiconductor device includes forming a plurality of trenches, including applying a first mask, forming a first polysilicon region in at least some of the plurality of trenches, forming a inter-polysilicon dielectric region and a termination protection region, including applying a second mask, forming a second polysilicon region in the at least some of the plurality of trenches, forming a first electrical contact to the first polysilicon region and forming a second electrical contact to the second polysilicon region, including applying a third mask, disposing a metal layer, and forming a source metal region and a gate metal region, including applying a fourth mask.02-17-2011
20110068386DIRECT CONTACT IN TRENCH WITH THREE-MASK SHIELD GATE PROCESS - A semiconductor device and a method for making a semiconductor device are disclosed. A trench mask may be applied to a semiconductor substrate, which is etched to form trenches with three different widths. A first conductive material is formed at the bottom of the trenches. A second conductive material is formed over the first conductive material. An insulator layer separates the first and second conductive materials. A first insulator layer is deposited on top of the trenches. A body layer is formed in a top portion of the substrate. A source is formed in the body layer. A second insulator layer is applied on top of the trenches and the source. A contact mask is applied on top of the second insulator layer. Source and gate contacts are formed through the second insulator layer. Source and gate metal are formed on top of the second insulator layer.03-24-2011
20110140167Nanotube Semiconductor Devices - A method for forming a semiconductor device includes forming a nanotube region using a thin epitaxial layer formed on the sidewall of a trench in the semiconductor body. The thin epitaxial layer has uniform doping concentration. In another embodiment, a first thin epitaxial layer of the same conductivity type as the semiconductor body is formed on the sidewall of a trench in the semiconductor body and a second thin epitaxial layer of the opposite conductivity type is formed on the first epitaxial layer. The first and second epitaxial layers have uniform doping concentration. The thickness and doping concentrations of the first and second epitaxial layers and the semiconductor body are selected to achieve charge balance. In one embodiment, the semiconductor body is a lightly doped P-type substrate. A vertical trench MOSFET, an IGBT, a Schottky diode and a P-N junction diode can be formed using the same N-Epi/P-Epi nanotube structure.06-16-2011

Patent applications by Hong Chang, Cupertino, CA US