Various embodiments for improved power devices as well as their methods of manufacture, packaging and circuitry incorporating the same for use in a wide variety of power electronic applications are disclosed. One aspect of the invention combines a number of charge balancing techniques and other techniques for reducing parasitic capacitance to arrive at different embodiments for power devices with improved voltage performance, higher switching speed, and lower on-resistance. Another aspect of the invention provides improved termination structures for low, medium and high voltage devices. Improved methods of fabrication for power devices are provided according to other aspects of the invention. Improvements to specific processing steps, such as formation of trenches, formation of dielectric layers inside trenches, formation of mesa structures and processes for reducing substrate thickness, among others, are presented. According to another aspect of the invention, charge balanced power devices incorporate temperature and current sensing elements such as diodes on the same die. Other aspects of the invention improve equivalent series resistance (ESR) for power devices, incorporate additional circuitry on the same chip as the power device and provide improvements to the packaging of charge balanced power devices.

Power semiconductor devices and methods of manufacture

A semiconductor power device wherein the reverse voltage across the p + -regions(s) and the n + -regions(s) is sustained by a composite buffer layer, shortly as CB-layer. The CB-layer contains two kinds of semiconductor regions with opposite types of conduction. These two kinds of regions are alternatively arranged, viewed from any cross-section parallel to the interface between the layer itself and the n + (or p + )-region. Whereas the hitherto-used voltage sustaining layer contains only one kind of semiconductor with single type of conduction in the same sectional view. Design guidelines are also provided in this invention. The relation between the on-resistance in unit area Ron and the breakdown voltage V B of the CB-layer invented is Ron ocV B 113 which represents a breakthrough to the conventional voltage sustaining layer, whereas the other performances of the power devices remain almost unchanged.

Semiconductor power devices with alternating conductivity type high-voltage breakdown regions

An austenitic stainless steel, which consists of by mass percent, C: not more than 0.02%, Si: not more than 1.5%, Mn: not more than 2%, Cr: 17 to 25%, Ni: 9 to 13%, Cu: more than 0.26% not more than 4%, N: 0.06 to 0.35%, sol. Al: 0.008 to 0.03%. One or more elements selected from Nb, Ti, V, TA, Hf, and Zr in controlled amounts can be included with the balance being Fe and impurities. P, S, Sn, As, Zn, Pb and Sb among the impurities are controlled as P: 0.006 to 0.04%, S: 0.0004 to 0.03%, Sn: 0.001 to 0.1%, As: not more than 0.01%, Zn: not more than 0.01%, Pb: not more than 0.01% and Sb: not more than 0.01%. The amounts of S, P, Sn, As, Zn, Pb and Sb and the amounts of Nb, Ta, Zr, Hf, and Ti are further controlled using formulas.

Austenitic stainless steel

A power device includes a semiconductor region which in turn includes a plurality of alternately arranged pillars of first and second conductivity type. Each of the plurality of pillars of second conductivity type further includes a plurality of implant regions of the second conductivity type arranged on top of one another along the depth of pillars of second conductivity type, and a trench portion filled with semiconductor material of the second conductivity type directly above the plurality of implant regions of second conductivity type.

Superjunction Structures for Power Devices and Methods of Manufacture

An epoxy resin composition comprising (a) an epoxy resin, (b) a lactone obtained by decarboxylation condensation reaction of a saturated alicyclic 1,2-dicarboxylic acid anhydride, and if necessary (c) a curing agent for the epoxy resin and (d) a curing accelerator gives a cured article showing almost no or very slight curing shrinkage

Epoxy resin composition

A heat resisting steel suitable for use as material of steam turbine parts The steel has a substantially whole tempered martensite structure and consisting essentially of, by weight, 8 to 13% of Cr, 05 to 2% of Mo, 002 to 05% of V, 002 to 015% of Nb, 0025 to 01% of N, 005 to 025% of C, not greater than 06% of Si, not greater than 15% of Mn, not greater than 15% of Ni, 00005 to 002% of Al, 01 to 05% of W and the balance substantially Fe, the ratio W/Al between W content and Al content ranging between 10 and 110

Heat resisting steel

A welded structure and a method for making same wherein a plurality of weld metals, such as martensitic steel and austenitic steel, differing in coefficient of thermal expansion from each other are deposited in a plurality of layers thicknesswise of the welded structure in a gap defined by structural members to be welded in such a manner that a layer of the weld metal of higher coefficient of thermal expansion is covered by a layer of the weld metal of lower coefficient of thermal expansion in a weld formed, to improve brittle fracture strength, fatigue strength and stress corrosion cracking resistance of the weld. By subjecting the welded structure to stress relief annealing treatment, it is possible to produce compressive stress on the surface of the layer of the weld metal of lower coefficient of thermal expansion.

Welded structrue having improved mechanical strength and process for making same

PURPOSE: To provide high creep rupture strength and high toughness at room temp. to a Cr-Ni-Mo-V-Nb-N steel by adding a very small amount of a rare earth element or Ca to the steel. CONSTITUTION: The composition of a steel is composed of, by weight, 0.05W0.25% C, ≤0.3% Si, ≤1.5% Mn, 1.0W2.5% Ni, 8W13% Cr, 1.0W2.5% Mo, 0.05W0.35% V, 0.02W0.20% Nb and/or Ta, 0.01W0.10% N, at least one between ≤0.3% rare earth element and ≤0.01% Ca and the balance Fe with inevitable impurities, and a total tempered martensite structure is practically formed as the structure of the steel. Thus, a heat resistant steel having ≥50kg/mm 2 creep rupture strength after the lapse of 10 5 hr at 450°C and >4kg-m absorption energy in a V notch Charpy impact test at 25°C can be obtd. The heat resistant steel is suitable for use as a material for a high-speed rotating body such as a gap turbine disk. COPYRIGHT: (C)1987,JPO&Japio

Heat resistant steel

This invention discloses martensitic heat-resistant steel consisting essentially of 0.1 to 0.2 wt.% of C, up to 0.4 wt.% of Si, up to 1 wt.% of Mn, 9 to 12 wt.% of Cr, 0.1 to 0.3 wt.% of V, 0.02 to 0.25 wt.% of Nb, 0.03 to 0.1 wt.% of N, up to 1 wt.% of Ni, molybdenum and tungsten in amounts falling within the range encompassed by lines connecting a point A (0.7 wt.% of Mo and 1.1 wt.% of W), a point B (1.2 wt.% of Mo and 1.1 wt.% of W), a point C (1.6 wt.% of Mo and 0.33 wt.% of W) and a point D (0.7 wt.% of Mo and 0.33 wt.% of W) as shown in Figure 1 and the balance of iron. The martensitic heat-resistant steel in accordance with the present invention is suitable for use in steam turbine blades and rotor shafts.

Martensitic heat-resistant steel

A steam turbine rotor shaft made of precipitation-hardened forged austenite steel, comprising first, second and succeeding layers of build-up welding provided on an outer surface of a bearing portion of a journal section in the rotor shaft, the first layer being provided by use of a welding rod of Ni base alloy, the second and succeeding layers being provided by use of a welding rod of low alloy steel which layers have better bearing characteristics than those of the austenite steel.

Seishin Kirihara

Papers

Heat resisting steel

Welded structrue having improved mechanical strength and process for making same

Heat resistant steel

Martensitic heat-resistant steel

Steam turbine rotor shaft