Alpha & Omega Semiconductor Patent Grants

High density trench-based power MOSFETs with self-aligned active contacts and method for making such devices

Granted: November 17, 2015
Patent Number: 9190512
Aspects of the present disclosure describe a high density trench-based power MOSFET with self-aligned source contacts. The source contacts are self-aligned with a first insulative spacer and a second insulative spacer, wherein the first spacer is resistant to an etching process that will selectively remove the material the second spacer is made from. Additionally, the active devices may have a two-step gate oxide, wherein a lower portion of the gate oxide has a thickness T2 that is…

Method for forming dual oxide trench gate power MOSFET using oxide filled trench

Granted: November 17, 2015
Patent Number: 9190478
A method for forming a dual oxide thickness trench gate structure for a power MOSFET includes providing a semiconductor substrate; forming a first trench on a top surface of the substrate; forming a first oxide layer in the first trench where the first oxide layer has a first depth from the bottom of the first trench; forming a dielectric spacer along the sidewall of the first trench and on the first oxide layer; etching the first oxide layer exposed by the dielectric spacer to a second…

Semiconductor device employing trenches for active gate and isolation

Granted: November 17, 2015
Patent Number: 9190408
A semiconductor device with multiple transistor devices includes a semiconductor layer of a first conductivity type formed on a substrate; a first trench formed in the semiconductor layer including a first trench gate; a second trench formed in the semiconductor layer and extending into the substrate and including a second trench gate; a first transistor device being an LDMOS transistor formed in the semiconductor layer between the first trench and the second trench; and a second…

Stacked dual-chip packaging structure and preparation method thereof

Granted: November 10, 2015
Patent Number: 9184117
The invention relates to a power semiconductor device and a preparation method, particularly relates to preparation of stacked dual-chip packaging structure of MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) using flip chip technology with two interconnecting plates. The first chip is flipped and attached on the base such that the first chip is overlapped with the third pin; the back metal layer of the first chip is connected to the bonding strip of the first pin through a…

Semiconductor device including superjunction structure formed using angled implant process

Granted: October 27, 2015
Patent Number: 9171949
A semiconductor device includes a superjunction structure formed using simultaneous N and P angled implants into the sidewall of a trench. The simultaneous N and P angled implants use different implant energies and dopants of different diffusion rate so that after annealing, alternating N and P thin semiconductor regions are formed. The alternating N and P thin semiconductor regions form a superjunction structure where a balanced space charge region is formed to enhance the breakdown…

Edge termination configurations for high voltage semiconductor power devices

Granted: October 27, 2015
Patent Number: 9171917
This invention discloses a semiconductor power device disposed in a semiconductor substrate and having an active cell area and an edge termination area wherein the edge termination area comprises a wide trench filled with a field-crowding reduction filler and a buried field plate buried under a top surface of the semiconductor substrate and laterally extended over a top portion of the field crowding field to move a peak electric field laterally away from the active cell area. In a…

Semiconductor package with small gate clip and assembly method

Granted: October 27, 2015
Patent Number: 9171788
A method of manufacturing a semiconductor package having a small gate clip is disclosed. A first and second semiconductor chips, each of which includes a source electrode and a gate electrode at a top surface, are attached on two adjacent lead frame units of a lead frame such that the lead frame unit with the first chip formed thereon is rotated 180 degrees in relation to the other lead frame unit with the second semiconductor chip formed thereon. A first and second clip sets are mounted…

High voltage MOSFET diode reverse recovery by minimizing P-body charges

Granted: October 20, 2015
Patent Number: 9166042
This invention discloses a method for manufacturing a semiconductor power device in a semiconductor substrate comprises an active cell area and a termination area. The method comprises the steps of a) growing and patterning a field oxide layer in the termination area and also in the active cell area on a top surface of the semiconductor substrate b) depositing and patterning a polysilicon layer on the top surface of the semiconductor substrate at a gap distance away from the field oxide…

Stacked dual chip package having leveling projections

Granted: October 20, 2015
Patent Number: 9165866
The present invention is directed to a lead-frame having a stack of semiconductor dies with interposed metalized clip structure. Level projections extend from the clip structure to ensure that the clip structure remains level during fabrication.

Top drain LDMOS

Granted: October 13, 2015
Patent Number: 9159828
In an embodiment, this invention discloses a top-drain lateral diffusion metal oxide field effect semiconductor (TD-LDMOS) device supported on a semiconductor substrate. The TD-LDMOS includes a source electrode disposed on a bottom surface of the semiconductor substrate. The TD-LDMOS further includes a source region and a drain region disposed on two opposite sides of a planar gate disposed on a top surface of the semiconductor substrate wherein the source region is encompassed in a body…

Alternating current injection for constant-on time buck converter—a regulator control method

Granted: October 6, 2015
Patent Number: 9154034
The present invention discloses a voltage control method. At first, the load voltage of the load is divided to generate a feedback voltage. The feedback voltage and a triangular wave of a triangular wave periodic signal, including the positive voltage and negative voltage, are combined to generate a sum signal. The sum signal is compared with a target voltage, and when the sum signal is less than the target voltage signal, a control signal is generated to control the switches to turn on…

Termination design by metal strapping guard ring trenches shorted to a body region to shrink termination area

Granted: October 6, 2015
Patent Number: 9153653
This invention discloses a semiconductor power device formed in a semiconductor substrate of a first conductivity type comprises an active cell area and a termination area surrounding the active cell area and disposed near edges of the semiconductor substrate. The termination area includes a plurality of trenches filled with a conductivity material forming a shield electrode and insulated by a dielectric layer along trench sidewalls and trench bottom surface wherein the trenches…

Closed cell configuration to increase channel density for sub-micron planar semiconductor power device

Granted: September 29, 2015
Patent Number: 9147674
A semiconductor power device supported on a semiconductor substrate that includes a plurality of transistor cells, each cell has a source and a drain region disposed on opposite sides of a gate region in the semiconductor substrate. A gate electrode is formed as an electrode layer on top of the gate region for controlling an electric current transmitted between the source and the drain regions. The gate electrode layer disposed on top of the semiconductor substrate is patterned into a…

Multi-die power semiconductor device packaged on a lead frame unit with multiple carrier pins and a metal clip

Granted: September 29, 2015
Patent Number: 9147648
A power semiconductor device comprises a lead frame unit, a control die, a first MOSFET die and a second MOSFET die, wherein the lead frame unit comprises at least a die paddle for mounting the first and second MOSFET dies, a first pin and a second pin for connecting to top electrodes of the first and second MOSFET dies, a first row of carrier pins and a second row of carrier pins disposed in-line with the first and second pins respectively for the control die to mount thereon.

Semiconductor package with connecting plate for internal connection

Granted: September 29, 2015
Patent Number: 9147586
A semiconductor package with connecting plate for internal connection comprise: a plurality of chips each having a plurality of contact areas on a top surface; one or more connecting plates having a plurality of electrically isolated connecting plate portions each connecting a contact area of the semiconductor chips. The method of making the semiconductor package includes the steps of connecting one or more connecting plates to a plurality of semiconductor chips, applying a molding…

Substrateless power device packages

Granted: September 15, 2015
Patent Number: 9136154
A substrate-less composite power semiconductor device may be fabricated from a vertical conductive power semiconductor device wafer that includes a top metal layer located on a top surface of the wafer by a) forming solder bumps on top of the top metal layer; b) forming wafer level molding around the solder bumps such that the solder bumps are exposed through a top of the wafer level molding; c) grinding a back side of the device wafer to reduce a total thickness of a semiconductor…

Device structure and methods of making high density MOSFETs for load switch and DC-DC applications

Granted: September 15, 2015
Patent Number: 9136380
Aspects of the present disclosure describe a high density trench-based power MOSFETs with self-aligned source contacts and methods for making such devices. The source contacts are self-aligned with spacers that are formed along the sidewall of the gate caps. Additionally, the active devices may have a two-step gate oxide. A lower portion may have a thickness that is larger than the thickness of an upper portion of the gate oxide. The two-step gate oxide combined with the self-aligned…

Bottom source substrateless power MOSFET

Granted: September 15, 2015
Patent Number: 9136379
A bottom source power metal-oxide-semiconductor field-effect transistor (MOSFET) device includes a gate electrode and a source electrode formed on an initial insulation layer on a first surface of a semiconductor chip and a drain electrode formed on a second surface of the semiconductor chip. The source electrode includes a source metal, a source electrode bump formed on the source metal and a source electrode metal layer on top of the source electrode bump. A first insulation layer…

High density MOSFET array with self-aligned contacts delimited by nitride-capped trench gate stacks and method

Granted: September 15, 2015
Patent Number: 9136377
A high density trench-gated MOSFET array and method are disclosed. It comprises semiconductor substrate partitioned into MOSFET array area and gate pickup area; epitaxial region, body region and source region; numerous precisely spaced active nitride-capped trench gate stacks (ANCTGS) embedded till the epitaxial region. Each ANCTGS comprises a stack of polysilicon trench gate with gate oxide shell and silicon nitride cap covering top of polysilicon trench gate and laterally registered to…

Shielded gate trench MOSFET package

Granted: September 15, 2015
Patent Number: 9136370
A trench formed in a body layer and epitaxial layer of a substrate is lined with a dielectric layer. A shield electrode formed within a lower portion of the trench is insulated by the dielectric layer. A gate electrode formed in the trench above the shield electrode is insulated from the shield electrode by another dielectric layer. One or more source regions formed within the body layer is adjacent a sidewall of the trench. A source pad formed above the body layer is electrically…