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

In accordance with an embodiment of the present invention, a MOSFET includes a first semiconductor region of a first conductivity type, a gate trench which extends into the first semiconductor region, and a source trench which extends into the first semiconductor region. The source trench is laterally spaced from the gate trench.

Dual trench power MOSFET

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

To provide a super-junction MOSFET reducing the tradeoff relation between the on-resistance and the breakdown voltage greatly and having a peripheral structure, which facilitates reducing the leakage current in the OFF-state thereof and stabilizing the breakdown voltage thereof. The vertical MOSFET according to the invention includes a drain drift region including a first alternating conductivity type layer; a breakdown withstanding region (peripheral region) including a second alternating conductivity type layer around drain drift region, second alternating conductivity type layer being formed of layer-shaped vertically-extending n-type regions and layer-shaped vertically-extending p-type regions laminated alternately; an n-type region around second alternating conductivity type layer; and a p-type region formed in the surface portion of n-type region to reduce the leakage current in the OFF-state of the MOSFET.

Super-junction semiconductor device

In a power converting apparatus which converts AC power into DC power, an inverter circuit including at least one series-connected single-phase inverter is connected in a downstream of a stage in which an AC input is rectified in series therewith. In the downstream stage of the inverter circuit, there are provided a smoothing capacitor connected via a rectifier diode and a short-circuiting switch for bypassing the smoothing capacitor. The short-circuiting switch is set to an ON state only in each of short-circuiting phase ranges of which midpoint matches each of zero-crossing phases and an output of the inverter circuit is controlled by using a current command so that a DC voltage of the smoothing capacitor follows a target voltage and an input power factor is improved.

Power converting apparatus

PROBLEM TO BE SOLVED: To reduce generation loss, improve conversion efficiency, simplify constitution, and realize miniaturization or the like. SOLUTION: In a soft switching circuit, in which a capacitor is connected in parallel with a switching element and made to perform resonance operation with a reactor, an element which is called a superjunction MOSFET which has small on-resistance and a large output capacitance is used as a switching element Q2. As a result, current conduction loss is reduced, and large output capacitance is used, so that a parallel capacitor which is connected in parallel with the element Q2 in the conventional circuit can be omitted.

Soft switching circuit

PROBLEM TO BE SOLVED: To reduce a noise current flowing through a power converter more simply and inexpensively than by a conventional circuit. SOLUTION: In the power converter consisting of a rectification circuit 2 connected to an AC power source 1, and a smoothing capacitor C 0 and an inverter circuit 3 which are connected to the DC output of the circuit 2, for example, a serial circuit consisting of a reactor L 1 and a capacitor C 1 is connected between the negative pole side of e.g. an AC output terminal and a ground G so that an impedance can have the extremely small value in a resonant frequency determined by the inductance of the reactor L 1 and the capacitance of the capacitor C 1 , thereby bypassing more common mode currents. In this way, the apparatus which is simpler, smaller and lower-cost than a conventional apparatus using a serial circuit of an MOSFET can be realized. COPYRIGHT: (C)2003,JPO

Noise reducing apparatus for power converter

PROBLEM TO BE SOLVED: To provide a conductive noise filter that compensates a leakage current on the power supply side and reduces a voltage for compensation SOLUTION: The conductive noise filter is applied to a system including: a rectifier 4 that converts the output of an AC power supply 1 into DC voltage; and a power converter 6 that converts a DC voltage into an AC voltage by switching operation of a power semiconductor element The noise filter includes: a common mode voltage detecting means 15 that detects common mode voltage produced during switching operation of the power semiconductor element through a ground capacitor 14 connected to a line 3 between the AC power supply 1 and the rectifier 4; and a compensation voltage source 8 that generates voltage for compensation identical in magnitude with the common mode voltage and opposite in polarity to the common mode based on detected common mode voltage and superimposes this voltage for compensation onto between the AC power supply 1 and the junction point of the ground capacitor 14 in the line 3 to cancel out the common mode voltage COPYRIGHT: (C)2010,JPO&INPIT

Conductive noise filter

PROBLEM TO BE SOLVED: To reduce the size of a power converter and balance the steady currents of a plurality of semiconductor switches connected in parallel to each other with high precision. SOLUTION: A device steady current balance control circuit has sample holding circuits 61 -6n which sample sensed voltages when respective devices to which sensing resistors for current detection are connected are turned on, amplifiers 71 -7n which amplify steady state sensed voltages by gains corresponding to the sensed voltages held by the circuits 61 -6n , an average calculation circuit 10 which calculates the average of the outputs of the amplifiers 71 -7n , comparators 81 -8n which compare the outputs of the amplifiers 71 -7n with the output of the circuit 10 and gate voltage adjustment circuits 91 -9n which adjust the driving voltages of the respective devices so as to have respective inputs of the comparators 81 -8n equal to each other.

Device steady current balance control circuit of the power converter

PROBLEM TO BE SOLVED: To prevent the generation of element destruction without deviating from a safe operation area at the time of the overcurrent at the time of adding a sense IGBT(insulated gate bipolar transistor) to a main IGBT chip and equivalently detecting the collector current of the main IGBT from a sense current. SOLUTION: By connecting an MOSFETT1 between the emitter Es of the sense IGBT and the emitter E of the main IGBT and using it as a variable sense resistor, regardless of the size of the collector emitter voltage of the main IGBT, the collector current of the main IGBT is limitd to an almost fixed value. In such a manner, even for a normal IGBT without a built-in sense IGBT, overcurrent protection is performed.

Masateru Igarashi

Papers

Soft switching circuit

Noise reducing apparatus for power converter

Conductive noise filter

Device steady current balance control circuit of the power converter

Overcurrent protection circuit