National Semiconductor Corporation

Texas Instruments Corporation

Andy Strachan

Peter J Hopper

Vladislav Vashchenko

Philipp Lindorfer

Charles A Dark

Douglas Brisbin

Alexei Sadovnikov

William Max Coppock

Jeffery Lee Nilles

Lisa V Rozario

Peter B Johnson

Yuri Mirgorodski

Kyuwoon Hwang

Richard Wendell Foote, Jr

Alexander H Owens

Lily Springer

He Lin

Terry Lee Lines

Dening Wang

Wipawan Yindeepol

Gang Xue

David Tsuei

Richard Orr

Kun Chen

Chao Wu

A contact array optimization scheme for ESD devices. In one embodiment, contact apertures patterned through a pre-metal dielectric layer over active areas may be selectively modified in size, shape, placement and the like, to increase ESD protection performance, e.g., such as maximizing the transient current density, etc., in a standard ESD rating test.

Contact array optimization for ESD devices

A system and method is disclosed that prevents the formation of a vertical bird's beak structure in the manufacture of a semiconductor device. A polysilicon filled trench is formed in a substrate of the semiconductor device. One or more composite layers are then applied over the trench and the substrate. A mask and etch process is then applied to etch the composite layers adjacent to the polysilicon filled trench. A field oxide process is applied to form field oxide portions in the substrate adjacent to the trench. Because no field oxide is placed over the trench there is no formation of a vertical bird's beak structure. A gate oxide layer is applied and a protection cap is formed over the polysilicon filled trench to protect the trench from unwanted effects of subsequent processing steps.

System and method for providing a poly cap and a no field oxide area to prevent formation of a vertical bird's beak structure in the manufacture of a semiconductor device

A test structure and testing method are provided for characterizing the time-dependent drift in the parasitic PFET leakage current that flows along the sidewall of a deep trench isolation structure from the P-type active area to the P-type substrate in a semiconductor integrated circuit structure. The capacitive coupling characteristics of the deep trench isolation structure are used to control the electrical 'bias' of the deep trench structure through the use of a large auxiliary trench mesh network that is formed as part of the deep trench structure. The trench mesh network can be placed adjacent to a Vdd ring or a ground ring and then, by using a ratioed capacitive voltage dividing network, the electrical potential at the trench can be controlled.

Electrical test structure and method for characterization of deep trench sidewall reliability

An efficient method is disclosed for increasing the breakdown voltage of an integrated circuit device that is isolated by a local oxidation of silicon (LOCOS) process. The method comprises forming a portion of a field oxide in an integrated circuit so that the field oxide has a gradual profile. The gradual profile of the field oxide reduces impact ionization in the field oxide by creating a reduced value of electric field for a given value of applied voltage. The reduction in impact ionization increases the breakdown voltage of the integrated circuit. The gradual profile is formed by using an increased thickness of pad oxide and a reduced thickness of silicon nitride during a field oxide oxidation process.

System and method for increasing breakdown voltage of LOCOS isolated devices

In a BSCR or BJT ESD clamp, the breakdown voltage and DC voltage tolerance are controlled by controlling the size of the collector of the BJT device by masking part of the collector.

Method of controlling the breakdown voltage of BSCRs and BJT clamps

A silicide bridged anti-fuse and a method of forming the anti-fuse are disclosed. The silicide bridged anti-fuse can be formed with a tungsten plug metalization process that does not require any additional process steps. As a result, anti-fuses can be added to an electrical circuit as trim elements for no additional cost.

Method of forming a silicide bridged anti-fuse with a tungsten plug metalization process

A MOS transistor and subsurface collectors can be formed by using a hard mask and precisely varying the implant angle, rotation, dose, and energy. In this case, a particular atomic species can be placed volumetrically in a required location under the hard mask. The dopant can be implanted to form sub-silicon volumes of arbitrary shapes, such as pipes, volumes, hemispheres, and interconnects.

Method of forming a circuit having subsurface conductors

The trench leakage current of a deep trench isolation structure is measured. The deep trench isolation structure, which is filled with polysilicon, contacts both a first region of a first conductivity type and a second region of a second conductivity type, and is proximate to a third region of the first conductivity type formed in the second region. Test voltages are applied to the structures and the leakage current is measured.

Method of measuring the leakage current of a deep trench isolation structure

When a high-voltage, such as from an ESD pulse, is placed across a silicon controlled rectifier, which includes an NPN transistor and a PNP transistor that is connected to the NPN transistor, the likelihood of punch through occurring between two regions of the rectifier is substantially reduced by forming the emitter of one transistor adjacent to the tails of the sinker down region of the other transistor.

Method of forming a high-voltage silicon controlled rectifier structure with improved punch through resistance

The drain breakdown voltage walk-in of a dual-source, dual-gate PMOS transistor is significantly reduced by utilizing source regions which have a width that is equal to or less than a width of the drain region. By utilizing source regions with widths that are equal to or less than the width of the drain region, the current density in the drain region is significantly reduced which reduces the number of hot charge carriers that are trapped at the silicon-to-silicon dioxide interface which, turn in, reduces the drain breakdown voltage walk-in rate.

Multi-source, multi-gate MOS transistor with a drain region that is wider than the source regions

A power transistor structure uses metal drain and source strips with non-uniform widths to reduce variations in current density across the power transistor structure. The reductions in current density, in turn, reduce the source-to-drain turn on resistance and maximize the overall current carrying capacity of power transistor structure.

Method of forming a semiconductor structure with non-uniform metal widths

A single junction interdigitated photodiode utilizes a stack of alternating highly doped first regions of a first conductivity type and highly doped second regions of a second conductivity type, which are formed below and contact the first regions, to collect photons. In addition, a highly doped sinker of a first conductivity type contacts each first region, and a highly doped sinker of a second conductivity type contacts each second region.

Vertical photodiode with heavily-doped regions of alternating conductivity types

In an integrated circuit, dopant concentration levels are adjusted by making use of a perforated mask. Doping levels for different regions across an integrated circuit can be differently defined by making use of varying size and spacings to the perforations in the mask. The diffusion of dopant is completed by making use of an annealing stage.

Single mask control of doping levels

In a zener zap diode device and a system for making such a device using a double poly process, p+ and n+regions are formed in a tub by means of p-doped and n-doped polysilicon regions, and a p-n junction is formed between the p+ region and an n-tub or between the n+ region and a p-tub. Cobalt or other refractory metal is reacted with silicon to form a silicide on at least the p-doped polysilicon region. By reverse biasing the p-n junction and establishing a sufficiently high zap current, the silicide can be forced to migrate across the junction to form a silicide bridge thereby selectively shorting out the p-n junction.

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Santa Clara, CA, United States of America

Andy Strachan