Apd Semiconductor, Inc.

Advanced Power Devices, Inc.

Diodes Inc.

Other

Wayne Y W Hsueh

Vladimir Rodov

Paul C Chang

Geeng-Chuan Chern

Charles Lin

Prognyan Ghosh

Michael Chern

Hidenori Akiyama

Jianren Bao

Arthur Ching-Lang Chiang

Yasuo Ohtsuki

Haru Ohkawa

Geeng-Chuan (aka Michael) Chern

A method of fabricating a semiconductor integrated circuit including a power diode includes providing a semiconductor substrate of first conductivity type, fabricating a integrated circuit such as a CMOS transistor circuit in a first region of the substrate, and fabricating a power diode in a second region in the semiconductor substrate. Dielectric material is formed between the first region and the second regions thereby providing electrical isolation between the integrated circuit in the first region and the power diode in the second region. The power diode can comprise a plurality of MOS source/drain elements and associated gate elements all connected together by one electrode of the diode, and a semiconductor layer in the second region can function as another source/drain of the power diode.

Integrated circuit including power diode

A vertical semiconductor rectifier device includes a semiconductor substrate of first conductivity type and having a plurality of gates insulatively formed on a first major surface and a plurality of source/drain regions of the first conductivity type formed in surface regions of second conductivity type in the first major surface adjacent to the gates. A plurality of channels of the second conductivity type each abuts a source/drain region and extends under a gate, each channel being laterally graded with a sloped P-N junction sepcarating the channel region from the substrate of first conductivity type, In fabricating the vertical semiconductor rectifier device, a partial ion mask is formed on the surface of the semiconductor with the mask having a sloped surface which varies the path length of ions through the mask to form laterally-graded channel regions.

Method of fabricating power rectifier device to vary operating parameters and resulting device

A two-terminal power diode has improved reverse bias breakdown voltage and on resistance includes a semiconductor body having two opposing surfaces and a superjunction structure therebetween, the superjunction structure including a plurality of alternating P and N doped regions aligned generally perpendicular to the two surfaces. The P and N doped regions can be parallel stripes or a mesh with each region being surrounded by doped material of opposite conductivity type. A diode junction associated with one surface can be an anode region with a gate controlled channel region connecting the anode region to the superjunction structure. Alternatively, the diode junction can comprise a metal forming a Schottky junction with the one surface. The superjunction structure is within the cathode and spaced from the anode. The spacing can be varied during device fabrication.

Power diode having improved on resistance and breakdown voltage

A vertical semiconductor rectifier device includes a semiconductor substrate of first conductivity type and having a plurality of gates insulatively formed on a first major surface and a plurality of source/drain regions of the first conductivity type formed in surface regions of second conductivity type in the first major surface adjacent to the gates. A plurality of channels of the second conductivity type each abuts a source/drain region and extends under a gate, each channel being laterally graded with a sloped P-N junction separating the channel region from the substrate of first conductivity type. In fabricating the vertical semiconductor rectifier device, a partial ion mask is formed on the surface of the semiconductor with the mask having a sloped surface which varies the path length of ions through the mask to form laterally-graded channel regions.

Method of fabricating power rectifier device having a laterally graded P-N junction for a channel region

A method for manufacturing a discrete power rectifier device having a VLSI multi-cell design employs a two spacer approach to defining a P/N junction profile having good breakdown voltage characteristics. The method provides highly repeatable device characteristics at reduced cost. The active channel regions of the device are also defined using the same two spacers. The method is a self-aligned process and channel dimensions and doping characteristics may be precisely controlled despite inevitable process variations in spacer formation. Only two masking steps are required, and additional spacers for defining the body region profile can be avoided, reducing processing costs.

Method of fabricating power VLSI diode devices

A power rectifier having low on resistance, fast recovery time and low forward voltage drop. In a preferred embodiment, the present invention provides a power rectifier device employing a vertical device structure, i.e., with current flow between the major surfaces of the discrete device. The device employs a large number of parallel connected cells, each comprising a MOSFET structure with a gate to drain short via a common conductive layer. This provides a low V path through the channel regions of the MOSFET cells to the contact metallization on the other side of the integrated circuit. A thin gate structure is formed annularly around pedestal regions on the upper surface of the device and a precisely controlled body implant defines the channel region and allows controllable device characteristics, including gate threshold voltage and V .

Discrete integrated circuit rectifier device

A semiconductor rectifying device which emulates the characteristics of a low forward voltage drop Schottky diode and which is capable of a variety of electrical characteristics from less than 1 A to greater than 1000 A current with adjustable breakdown voltage. The manufacturing process provides for uniformity and controllability of operating parameters, high yield, and readily variable device sizes. The device includes a semiconductor body with a guard ring on one surface to define a device region in which are optionally formed a plurality of conductive plugs. Between the guard ring and the conductive plugs are a plurality of source/drain, gate and channel elements which function with the underlying substrate in forming a MOS transistor. The channel regions are defined by using the photoresist mask for the gate oxide with the photoresist mask isotropically etched to expose a peripheral portion of the gate oxide (and gate electrode) with ions thereafter implanted through the exposed gate for forming the channel region. The source/drain (e.g. source) regions can be formed by ion implantation or by out-diffusion from a doped polysilicon layer.

A Schottky diode comprises a semiconductor body of one conductivity type, the semiconductor body having a grooved surface, a metal layer on the grooved surface and forming a Schottky junction with sidewalls of the grooved surface and ohmic contacts with top portions of the grooved surface. The semiconductor body preferably includes a silicon substrate with the grooved surface being on a device region defined by a guard ring of a conductivity type opposite to the conductivity type of the semiconductor body, and a plurality of doped regions at the bottom of grooves and forming P-N junctions with the semiconductor body. The P-N junctions of the doped regions form carrier depletion regions across and spaced from the grooves to increase the reverse bias breakdown voltage and reduce the reverse bias leakage current. The ohmic contacts of the metal layer increase forward current and reduce forward voltage of the Schottky diode.

Schottky diode having increased forward current with improved reverse bias characteristics and method of fabrication

A Schottky diode comprises a semiconductor body of one conductivity type, the semiconductor body having a grooved surface, a metal layer on the grooved surface and forming a Schottky junction with the semiconductor body. The semiconductor body preferably includes a silicon substrate with the grooved surface being on a device region defined by a guard ring of a conductivity type opposite to the conductivity type of the semiconductor body, and a plurality of doped regions at the bottom of grooves and forming P-N junctions with the semiconductor body. The P-N junctions of the doped regions form carrier depletion regions across and spaced from the grooves to increase the reverse bias breakdown voltage and reduce the reverse bias leakage current.

Schottky diode having increased active surface area with improved reverse bias characteristics and method of fabrication

A Schottky diode comprises a semiconductor body of one conductivity type, the semiconductor body having a grooved surface, and a metal layer on the grooved surface and forming a Schottky junction with the semiconductor body. The semiconductor body preferably includes a silicon substrate with the grooved surface being on a device region defined by a guard ring of a conductivity type opposite to the conductivity type of the semiconductor body.

Schottky diode having increased active surface area and method of fabrication

A power rectifier having low on resistance, mass recovery times and low forward voltage drop. In a preferred embodiment, the present invention provides a power rectifier device employing a vertical device structure, i.e., with current flow between the major surfaces of the discrete device. The device employs a large number of parallel connected cells, each comprising a MOSFET structure with a gate to drain short via a common metallization. This provides a low V,path through the channel regions of the MOSFET cells to the source region on the other side of the integrated circuit. A thin gate structure is formed annularly around the pedestal regions on the upper surface of the device and a precisely controlled body implant defines the channel region and allows controllable device characteristics, including gate threshold voltage and V,. A parallel Schottky diode is also provided which increases the switching speed of the MOSFET cells. The present invention further provides a method for manufacturing a rectifier device which provides highly repeatable device characteristics and which can provide such devices at reduced cost. The active channel regions of the device are defined using pedestals in a double spacer, double implant self-aligned process. The channel dimensions and doping characteristics may be precisely controlled despite inevitable process variations in spacer sidewall formation. Only two masking steps are required, reducing processing costs.

Power rectifier device and method of fabricating power rectifier devices

A power rectifier having low on resistance, fast recovery times and very low forward voltage drop. In a preferred embodiment, the present invention provides a power rectifier device employing a vertical device structure, i.e., with current flow between the major surfaces of the discrete device. The device employs a large number of parallel connected cells, each comprising a MOSFET structure with a gate to drain short via a common metallization. A self aligned body implant and a shallow silicide drain contact region integrated with a metal silicide drain contact define a narrow channel region and allow very high cell density. This provides a low V,path through the channel regions of the MOSFET cells to the contact on the other side of the integrated circuit. The present invention further provides a method for manufacturing a rectifier device which provides the above desirable device characteristics in a repeatable manner. Also, only two masking steps are required, reducing processing costs.

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San Jose, CA, United States of America

Wayne Y W Hsueh