Abstract: A trench MOSFET device and process for making the same are described. The trench MOSFET has a substrate of a first conductivity type, an epitaxial layer of the first conductivity type over the substrate, the epitaxial layer having a lower majority carrier concentration than the substrate, a plurality of trenches within the epitaxial layer, a first insulating layer, such as an oxide layer, lining the trenches, a conductive region, such as a polycrystalline silicon region, within the trenches adjacent to the first insulating layer, and one or more trench body regions and one or more termination body regions provided within an upper portion of the epitaxial layer, the termination body regions extending into the epitaxial layer to a greater depth than the trench body regions.

Abstract: A Schottky rectifier is provided. The Schottky rectifier comprises: (a) a semiconductor region having first and second opposing faces, with the semiconductor region comprising a cathode region of first conductivity type adjacent the first face and a drift region of the first conductivity type adjacent the second face, and with the drift region having a lower net doping concentration than that of the cathode region; (b) one or more trenches extending from the second face into the semiconductor region and defining one or more mesas within the semiconductor region; (c) an insulating region adjacent the semiconductor region in lower portions of the trench; (d) and an anode electrode that is (i) adjacent to and forms a Schottky rectifying contact with the semiconductor at the second face, (ii) adjacent to and forms a Schottky rectifying contact with the semiconductor region within upper portions of the trench and (iii) adjacent to the insulating region within the lower portions of the trench.

Abstract: A trench DMOS transistor cell is provided, which is formed on a substrate of a first conductivity type. A body region, which has a second conductivity type, is located on the substrate. At least one trench extends through the body region and the substrate. An insulating layer lines the trench. The insulating layer includes first and second portions that contact one another at an interface. The first portion of the insulating layer has a layer thickness greater than the second portion. The interface is located at a depth above a lower boundary of the body region. A conductive electrode is formed in the trench so that it overlies the insulating layer. A source region of the first conductivity type is formed in the body region adjacent to the trench.

Abstract: A method of forming a trench DMOS transistor is provides which reduces punch-through. The method begins by providing a substrate of a first conductivity type. A body region, which has a second conductivity type, is formed on the substrate. A masking layer is formed which defines at least one trench. Next, the trench and an insulating layer that lines the trench are formed. A conductive electrode is then formed in the trench, which overlies the insulating layer. A source region of the first conductivity type is formed in the body region adjacent to the trench. The step of forming the trench includes the steps of etching the trench and smoothing the sidewalls of the trench with a sacrificial oxide layer before removal of the masking layer that defines the trench.

Abstract: A bi-directional transient voltage suppression device with symmetric current-voltage characteristics has a lower semiconductor layer of first conductivity type, an upper semiconductor layer of first conductivity type, and a middle semiconductor layer adjacent to and disposed between the lower and upper layers having a second opposite conductivity type, such that upper and lower p-n junctions are formed. The middle layer has a net doping concentration that is highest at a midpoint between the junctions. Furthermore, the doping profile along a line normal to the lower, middle and upper layers is such that, within the middle layer the doping profile on one side of a centerplane of the middle layer mirrors the doping profile on an opposite side. In addition, an integral of the net doping concentration of the middle layer taken over the distance between the junctions is such that breakdown, when it occurs, is punch through breakdown, rather than avalanche breakdown.

Abstract: Test structures for a high voltage MOSFET are provided that includes a substrate of a first conductivity type. An epitaxial layer also of the first conductivity type is deposited on the substrate. A plurality of trenches are located in the drift region of the epitaxial layer. The trenches, which extend toward the substrate from the first and second body regions, are filled with a material that includes a dopant of the second conductivity type. The dopant is diffused from the trenches into portions of the epitaxial layer adjacent the trenches. The test structures allow the simultaneous optimization of the breakdown voltage and on-resistance of the device.

Abstract: In a first aspect of the invention, a modified semiconductor substrate is provided. The modified substrate comprises: (1) a semiconductor substrate; (2) at least one buffer layer provided over at least a portion of the substrate; and (3) a plurality of trenches comprising (a) a plurality of internal trenches that extend into the semiconductor substrate and (b) at least one shallow peripheral trench that extends into the at least one buffer layer but does not extend into the semiconductor substrate. In another aspect, a method of selectively providing trenches in a semiconductor substrate is provided. According to a further aspect of the invention, a trench DMOS transistor structure that includes at least one peripheral trench and a plurality of internal trenches is provided.

Abstract: A semiconductor device includes a first region of semiconductor material, which is doped to a first concentration with a dopant of a first conductivity type. A gate trench formed within the first region has sides and a bottom. A drain access trench is also formed within the first region, which also has sides and a bottom. A second region of semiconductor material is located within the first region and adjacent to and near the bottom of the gate trench. The second region extends to a location adjacent to and near the bottom of the drain access trench. The second region is of the first conductivity type and has a higher dopant concentration than the first region. A gate electrode is formed within the gate trench. A layer of gate dielectric material insulates the gate electrode from the first and second regions. A drain region of semiconductor material is located within the drain access trench. The drain region is of a first conductivity type and has a higher dopant concentration than the first region.

Abstract: A trench MOSFET device and process for making the same are described. The trench MOSFET has a substrate of a first conductivity type, an epitaxial layer of the first conductivity type over the substrate, the epitaxial layer having a lower majority carrier concentration than the substrate, a plurality of trenches within the epitaxial layer, a first insulating layer, such as an oxide layer, lining the trenches, a conductive region, such as a polycrystalline silicon region, within the trenches adjacent to the first insulating layer, and one or more trench body regions and one or more termination body regions provided within an upper portion of the epitaxial layer, the termination body regions extending into the epitaxial layer to a greater depth than the trench body regions.

Abstract: A trench MOSFET includes a plurality of trench segments in an upper surface of an epitaxial layer, extending through a second conductivity type region into a first conductivity type epitaxial region, each segment at least partially separated from an adjacent segment by a terminating region, and the trench segments defining a plurality of polygonal body regions within the second conductivity type region. A first insulating layer at least partially lines each trench and a plurality of first conductive regions are provided within the trench segments adjacent to the first layer. Each of the conductive regions is connected to an adjacent conductive region by a connecting conductive region, overlying the terminating region, that bridges at least one of the terminating regions, and a plurality of first conductivity source regions are within upper portions of polygonal body regions and adjacent the trench segments, the source regions positioned outside the terminating regions.

Abstract: A power semiconductor device and a method of forming the same is provided. The method begins by providing a substrate of a first conductivity type and then forming a voltage sustaining region on the substrate. The voltage sustaining region is formed by depositing an epitaxial layer of a first conductivity type on the substrate and forming at least one trench in the epitaxial layer. A barrier material is deposited along the walls of the trench. A dopant of a second conductivity type is implanted through the barrier material into a portion of the epitaxial layer adjacent to and beneath the bottom of the trench. The dopant is diffused to form a first doped layer in the epitaxial layer and the barrier material is removed from at least the bottom of the trench. The trench is etched through the first doped layer and a filler material is deposited in the trench to substantially fill the trench, thus completing the voltage sustaining region.

Abstract: A trench DMOS transistor cell includes a substrate of a first conductivity type and a body region located on the substrate, which has a second conductivity type. At least one trench extends through the body region and the substrate. An insulating layer lines the trench and a conductive electrode is placed in the trench overlying the insulating layer. A source region of the first conductivity type is located in the body region adjacent to the trench. The source region includes a first layer and a second layer disposed over the first layer. The first layer has a lower dopant concentration of the first conductivity type relative to the dopant concentration of the second layer.

Abstract: A semiconductor device includes a first region of semiconductor material, which is doped to a first concentration with a dopant of a first conductivity type. A gate trench formed within the first region has sides and a bottom. A drain access trench is also formed within the first region, which also has sides and a bottom. A second region of semiconductor material is located within the first region and adjacent to and near the bottom of the gate trench. The second region extends to a location adjacent to and near the bottom of the drain access trench. The second region is of the first conductivity type and has a higher dopant concentration than the first region. A gate electrode is formed within the gate trench. A layer of gate dielectric material insulates the gate electrode from the first and second regions. A drain region of semiconductor material is located within the drain access trench. The drain region is of a first conductivity type and has a higher dopant concentration than the first region.

Abstract: A trench Schottky barrier rectifier and a method of making the same in which the rectifier has a semiconductor region having first and second opposing faces; the semiconductor region having a drift region of first conductivity type adjacent the first face and a cathode region of the first conductivity type adjacent the second face; the drift region having a lower net doping concentration than that of the cathode region. The rectifier also has a plurality of trenches extending into the semiconductor region from the first face; the trenches defining a plurality of mesas within the semiconductor region, and the trenches forming a plurality of trench intersections.

Abstract: A hybrid semiconductor device comprises four identical semiconductor diode chips each having top and bottom surfaces. Each chip is mounted on a respective mounting pad all of which lie in a common plane and, for ease of assembly, the four chips are mounted in identical top to bottom orientation, e.g., bottom surface down and electrically connected to the mounting pads. In one embodiment, the mounting pads for the chips and terminals for the device are integral with leads of a single (“component”) lead frame and various electrical connectors for the chips comprise bonding wires or stamped metal jumpers added to the workpiece after the chips are mounted on the lead frame. The metal jumpers can be provided on a separate “jumper” lead frame used in cooperation with the component lead frame, or the jumpers can comprise portions of leads of the single component lead frame. Printed circuit boards embodiments are also disclosed.

Abstract: A method of manufacturing one or more trench DMOS transistors is provided. In this method, one or more or more body regions adjacent one or more trenches are provided. The one or more trenches are lined with a first insulating layer. A portion of the first insulating layer is removed along at least the upper sidewalls of the trenches, exposing portions of the body regions. An oxide layer is then formed over at least the exposed portions of the body regions, resulting in regions of reduced majority carrier concentration within the body regions adjacent the oxide layer. This modification of the majority carrier concentration in the body regions is advantageous in that a low threshold voltage can be established within the DMOS transistor without resorting to a thinner gate oxide (which would reduce yield and switching speed) and without substantially increasing the likelihood of punch-through.

Abstract: A hybrid semiconductor device comprises four identical semiconductor diode chips each having top and bottom surfaces. Each chip is mounted on a respective mounting pad all of which lie in a common plane and, for ease of assembly, the four chips are mounted in identical top to bottom orientation, e.g., bottom surface down and electrically connected to the mounting pads. In one embodiment, the mounting pads for the chips and terminals for the device are integral with leads of a single (“component”) lead frame and various electrical connectors for the chips comprise bonding wires or stamped metal jumpers added to the workpiece after the chips are mounted on the lead frame. The metal jumpers can be provided on a separate “jumper” lead frame used in cooperation with the component lead frame, or the jumpers can comprise portions of leads of the single component lead frame. Printed circuit boards embodiments are also disclosed.

Abstract: A method for making trench DMOS is provided that utilizes polycide and refractory techniques to make trench DMOS which exhibit low gate resistance, low gate capacitance, reduced distributed RC gate propagation delay, and improved switching speeds for high frequency applications.

Abstract: For stripping selected chips from a wafer of diced chips adhered, bottom surface down, to a flexible, elastic membrane, the bottom surface of the membrane is disposed against an apertured plate of a vacuum chuck for firmly holding the membrane in place with a group of the chips directly overlying push-up pins vertically movable through slots through the apertured plate. Selected pins are fired upwardly with sufficient speed to dislodge struck chips, but not non-selected adjacent chips, off the membrane and to hurl them, in free flight, upwardly against an overlying chip catching member. The stripped and caught chips are then transferred for storage or use.

Abstract: Two phase bridge rectifier, plastic encapsulated devices having four external terminal leads are batch fabricated using a workpiece of three stacked together lead frames wherein, at each of a plurality of device sites on the workpiece, two, two-chip stacks of semiconductor diode chips are provided; each chip of each stack being sandwiched between respective pairs of bonding pads on either top and middle lead frames or middle and bottom lead frames. Each of the two bonding pads of the middle frame is connected to a respective integral terminal lead of the middle frame. An integral extension of a bonding pad of each of the top and bottom lead frames is bent out of the plane of its respective lead frame to include a flat terminal lead portion lying in the plane of the middle frame but not connected thereto. All four in-plane terminal leads include dam bars for use during device encapsulating; the dam bars from the top and bottom lead frames cooperating to form a single, in-plane dam bar.