Patent application number | Description | Published |
20080258213 | Shielded Gate Field Effect Transistor - A FET includes a trench in a semiconductor region. The trench has a lower portion with a shield electrode therein, and an upper portion with a gate electrode therein, where the upper portion is wider than the lower portion. The semiconductor region includes a substrate of a first conductivity type and a first silicon region of a second conductivity type over the substrate. The first silicon region has a first portion extending to a depth intermediate top and bottom surfaces of the gate electrode. The first silicon region has a second portion extending to a depth intermediate top and bottom surfaces of the shield electrode. The semiconductor region further includes a second silicon region of the first conductivity type between the lower trench portion and the second portion of the first silicon region that has a laterally-graded doping concentration decreasing in a direction away from the sidewalls of the lower trench portion. | 10-23-2008 |
20090111227 | Method for Forming Trench Gate Field Effect Transistor with Recessed Mesas Using Spacers - A method for forming a field effect transistor with an active area and a termination region surrounding the active area includes forming a well region in a first silicon region, where the well region and the first silicon region are of opposite conductivity type. Gate trenches extending through the well region and terminating within the first silicon region are formed. A recessed gate is formed in each gate trench. A dielectric cap is formed over each recessed gate. The well region is recessed between adjacent trenches to expose upper sidewalls of each dielectric cap. A blanket source implant is carried out to form a second silicon region in an upper portion of the recessed well region between every two adjacent trenches. A dielectric spacer is formed along each exposed upper sidewall of the dielectric cap, with every two adjacent dielectric spacers located between every two adjacent gate trenches forming an opening over the second silicon region. The second silicon region is recessed through the opening between every two adjacent dielectric spacers so that only portions of the second silicon region directly below the dielectric spacers remain. The remaining portions of the second silicon region form source regions. | 04-30-2009 |
20090191678 | Method of Forming a Shielded Gate Field Effect Transistor - A semiconductor region with an epitaxial layer extending over the semiconductor region is provided. A first silicon etch is performed to form an upper trench portion extending into and terminating within the epitaxial layer. A protective material is formed extending along sidewalls of the upper trench portion and over mesa regions adjacent the upper trench portion but not along a bottom surface of the upper trench portion. A second silicon etch is performed to form a lower trench portion extending from the bottom surface of the upper trench portion through the epitaxial layer and terminating within the semiconductor region, such that the lower trench portion is narrower than the upper trench portion. A two-pass angled implant of dopants of the first conductivity type is carried out to form a silicon region of first conductivity type along sidewalls of the lower trench portion, while the protective material blocks the implant dopants from entering the sidewalls of the upper trench portion and the mesa region adjacent the upper trench portion. | 07-30-2009 |
20090200606 | Power Device Edge Termination Having a Resistor with One End Biased to Source Voltage - A field effect transistor (FET) includes a source electrode for receiving an externally-provided source voltage. The FET further includes an active region and a termination region surrounding the active region. A resistive element is coupled to the termination region, wherein upon occurrence of avalanche breakdown in the termination region an avalanche current starts to flow in the termination region, and the resistive element is configured to induce a portion of the avalanche current to flow through the termination region and a remaining portion of the avalanche current to flow through the active region. During operation, one end of the resistive element is biased to the source voltage. | 08-13-2009 |
20090230465 | Trench-Gate Field Effect Transistors and Methods of Forming the Same - A field effect transistor includes a body region of a first conductivity type over a semiconductor region of a second conductivity type. A gate trench extends through the body region and terminates within the semiconductor region. At least one conductive shield electrode is disposed in the gate trench. A gate electrode is disposed in the gate trench over but insulated from the at least one conductive shield electrode. A shield dielectric layer insulates the at lease one conductive shield electrode from the semiconductor region. A gate dielectric layer insulates the gate electrode from the body region. The shield dielectric layer is formed such that it flares out and extends directly under the body region. | 09-17-2009 |
20100038708 | Method and Structure for Forming a Shielded Gate Field Effect Transistor - A method of forming a charge balance MOSFET includes the following steps. A substrate with an overlying epitaxial layer both of a first conductivity type, are provided. A gate trench extending through the epitaxial layer and terminating within the substrate is formed. A shield dielectric lining sidewalls and bottom surface of the gate trench is formed. A shield electrode is formed in the gate trench. A gate dielectric layer is formed along upper sidewalls of the gate trench. A gate electrode is formed in the gate trench such that the gate electrode extends over but is insulated from the shield electrode. A deep dimple extending through the epitaxial layer and terminating within the substrate is formed such that the deep dimple is laterally spaced from the gate trench. The deep dimple is filled with silicon material of the second conductivity type. | 02-18-2010 |
20100140696 | Trench-Based Power Semiconductor Devices With Increased Breakdown Voltage Characteristics - Exemplary power semiconductor devices with features providing increased breakdown voltage and other benefits are disclosed. | 06-10-2010 |
20100140697 | Trench-Based Power Semiconductor Devices with Increased Breakdown Voltage Characteristics - Exemplary power semiconductor devices with features providing increased breakdown voltage and other benefits are disclosed. | 06-10-2010 |
20100258855 | Field Effect Transistor with Self-aligned Source and Heavy Body Regions and Method of Manufacturing Same - A field effect transistor includes a plurality of trenches extending into a semiconductor region of a first conductivity type. The plurality of trenches include a plurality of gated trenches and a plurality of non-gated trenches. A body region of a second conductivity extends in the semiconductor region between adjacent trenches. A dielectric material fills a bottom portion of each of the gated and non-gated trenches. A gate electrode is disposed in each gated trench. A conductive material of the second conductivity type is disposed in each non-gated trench such that the conductive material and contacts corresponding body regions along sidewalls of the non-gated trench. | 10-14-2010 |
20100258862 | TRENCH-GATE FIELD EFFECT TRANSISTOR WITH CHANNEL ENHANCEMENT REGION AND METHODS OF FORMING THE SAME - A field effect transistor includes a body region of a first conductivity type in a semiconductor region of a second conductivity type. A gate trench extends through the body region and terminating within the semiconductor region. A source region of the second conductivity type extends in the body region adjacent the gate trench. The source region and an interface between the body region and the semiconductor region define a channel region therebetween which extends along the gate trench sidewall. A channel enhancement region of the second conductivity type is formed adjacent the gate trench. The channel enhancement region partially extends into a lower portion of the channel region to thereby reduce a resistance of the channel region. | 10-14-2010 |
20110089488 | Power Device with Improved Edge Termination - A field effect transistor includes an active region and a termination region surrounding the active region. A resistive element is coupled to the termination region, wherein upon occurrence of avalanche breakdown in the termination region an avalanche current starts to flow in the termination region, and the resistive element is configured to induce a portion of the avalanche current to flow through the termination region and a remaining portion of the avalanche current to flow through the active region. | 04-21-2011 |
20110177662 | Method of Forming Trench-Gate Field Effect Transistors - A method of forming a field effect transistor includes: forming a trench in a semiconductor region; forming a shield electrode in the trench; performing an angled sidewall implant of impurities of the first conductivity type to form a channel enhancement region adjacent the trench; forming a body region of a second conductivity type in the semiconductor region; and forming a source region of the first conductivity type in the body region, the source region and an interface between the body region and the semiconductor region defining a channel region therebetween, the channel region extending along the trench sidewall. The channel enhancement region partially extends into a lower portion of the channel region to thereby reduce a resistance of the channel region. | 07-21-2011 |
20110303975 | Field effect transistor with self-aligned source and heavy body regions - A field effect transistor includes a plurality of trenches extending into a semiconductor region of a first conductivity type. The plurality of trenches includes a plurality of gated trenches and a plurality of non-gated trenches. A body region of a second conductivity extends in the semiconductor region between adjacent trenches. A dielectric material fills a bottom portion of each of the gated and non-gated trenches. A gate electrode is disposed in each gated trench. A conductive material of the second conductivity type is disposed in each non-gated trench such that the conductive material and contacts corresponding body regions along sidewalls of the non-gated trench. | 12-15-2011 |
20120104490 | Trench-Gate Field Effect Transistors and Methods of Forming the Same - A field effect transistor includes a body region of a first conductivity type over a semiconductor region of a second conductivity type. A gate trench extends through the body region and terminates within the semiconductor region. At least one conductive shield electrode is disposed in the gate trench. A gate electrode is disposed in the gate trench over but insulated from the at least one conductive shield electrode. A shield dielectric layer insulates the at lease one conductive shield electrode from the semiconductor region. A gate dielectric layer insulates the gate electrode from the body region. The shield dielectric layer is formed such that it flares out and extends directly under the body region. | 05-03-2012 |
20120156845 | METHOD OF FORMING A FIELD EFFECT TRANSISTOR AND SCHOTTKY DIODE - A method for forming a field effect transistor and Schottky diode includes forming a well region in a first portion of a silicon region where the field effect transistor is to be formed but not in a second portion of the silicon region where the Schottky diode is to be formed. Gate trenches are formed extending into the silicon region. A recessed gate is formed in each gate trench. A dielectric cap is formed over each recessed gate. Exposed surfaces of the well region are recessed to form a recess between every two adjacent trenches. Without masking any portion of the active area, a zero-degree blanket implant is performed to form a heavy body region of the second conductivity type in the well region between every two adjacent trenches. | 06-21-2012 |
20120193748 | TRENCH-BASED POWER SEMICONDUCTOR DEVICES WITH INCREASED BREAKDOWN VOLTAGE CHARACTERISTICS - Exemplary power semiconductor devices with features providing increased breakdown voltage and other benefits are disclosed. | 08-02-2012 |
20120319197 | FIELD EFFECT TRANSISTOR AND SCHOTTKY DIODE STRUCTURES - In accordance with an embodiment a structure can include a monolithically integrated trench field-effect transistor (FET) and Schottky diode. The structure can include a first gate trench extending into a semiconductor region, a second gate trench extending into the semiconductor region, and a source region flanking a side of the first gate trench. The source region can have a substantially triangular shape, and a contact opening extending into the semiconductor region between the first gate trench and the second gate trench. The structure can include a conductor layer disposed in the contact opening to electrically contact the source region along at least a portion of a slanted sidewall of the source region, and the semiconductor region along a bottom portion of the contact opening. The conductor layer can form a Schottky contact with the semiconductor region. | 12-20-2012 |
20130043527 | SHIELDED GATE TRENCH MOSFET PACKAGE - A shielded gate trench field effect transistor can be formed on a substrate having an epitaxial layer on the substrate and a body layer on the epitaxial layer. A trench formed in the body layer and epitaxial layer is lined with a dielectric layer. A shield electrode is formed within a lower portion of the trench. The shield electrode is insulated by the dielectric layer. A gate electrode is formed in the trench above the shield electrode and insulated from the shield electrode by an additional 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 connected to the one or more source regions and insulated from the gate electrode and shield electrode. The source pad provides an external contact to the source region. A gate pad provides an external contact to the gate electrode. A shield electrode pad provides an external contact to the shield electrode. A resistive element can be electrically connected between the shield electrode pad and the source lead in the package. | 02-21-2013 |
20130075808 | Trench MOSFET with Integrated Schottky Barrier Diode - A Schottky diode includes a semiconductor layer formed on a semiconductor substrate; first and second trenches formed in the semiconductor layer where the first and second trenches are lined with a thin dielectric layer and being filled partially with a trench conductor layer and remaining portions of the first and second trenches are filled with a first dielectric layer; and a Schottky metal layer formed on a top surface of the semiconductor layer between the first trench and the second trench. The Schottky diode is formed with the Schottky metal layer as the anode and the semiconductor layer between the first and second trenches as the cathode. The trench conductor layer in each of the first and second trenches is electrically connected to the anode of the Schottky diode. In one embodiment, the Schottky diode is formed integrated with a trench field effect transistor on the same semiconductor substrate. | 03-28-2013 |
20130181282 | FIELD EFFECT TRANSISTOR WITH SELF-ALIGNED SOURCE AND HEAVY BODY REGIONS - A field effect transistor includes a plurality of trenches extending into a semiconductor region of a first conductivity type. The plurality of trenches includes a plurality of gated trenches and a plurality of non-gated trenches. A body region of a second conductivity extends in the semiconductor region between adjacent trenches. A dielectric material fills a bottom portion of each of the gated and non-gated trenches. A gate electrode is disposed in each gated trench. A conductive material of the second conductivity type is disposed in each non-gated trench such that the conductive material and contacts corresponding body regions along sidewalls of the non-gated trench. | 07-18-2013 |
20130200451 | NANO MOSFET WITH TRENCH BOTTOM OXIDE SHIELDED AND THIRD DIMENSIONAL P-BODY CONTACT - A semiconductor power device may include a lightly doped layer formed on a heavily doped layer. One or more devices are formed in the lightly doped layer. Each device may include a body region, a source region, and one or more gate electrodes formed in corresponding trenches in the lightly doped region. Each of the trenches has a depth in a first dimension, a width in a second dimension and a length in a third dimension. The body region is of opposite conductivity type to the lightly and heavily doped layers. The source region is formed proximate the upper surface. One or more deep contacts are formed at one or more locations along the third dimension proximate one or more of the trenches. The contacts extend in the first direction from the upper surface into the lightly doped layer and are in electrical contact with the source region. | 08-08-2013 |
20130248991 | STRUCTURE AND METHOD FOR FORMING TRENCH-GATE FIELD EFFECT TRANSISTOR - A field effect transistor (FET) includes a body region of a first conductivity type disposed within a semiconductor region of a second conductivity type and a gate trench extending through the body region and terminating within the semiconductor region. The FET also includes a flared shield dielectric layer disposed in a lower portion of the gate trench, the flared shield dielectric layer including a flared portion that extends under the body region. The FET further includes a conductive shield electrode disposed in the trench and disposed, at least partially, within the flared shield dielectric. | 09-26-2013 |
20140042532 | TRENCH-BASED POWER SEMICONDUCTOR DEVICES WITH INCREASED BREAKDOWN VOLTAGE CHARACTERISTICS - Exemplary power semiconductor devices with features providing increased breakdown voltage and other benefits are disclosed. | 02-13-2014 |
20140042536 | TRENCH-BASED POWER SEMICONDUCTOR DEVICES WITH INCREASED BREAKDOWN VOLTAGE CHARACTERISTICS - Exemplary power semiconductor devices with features providing increased breakdown voltage and other benefits are disclosed. | 02-13-2014 |
20140054691 | FIELD EFFECT TRANSISTOR WITH GATED AND NON-GATED TRENCHES - A field effect transistor includes a plurality of trenches extending into a semiconductor region of a first conductivity type. The plurality of trenches includes a plurality of gated trenches and a plurality of non-gated trenches. A body region of a second conductivity extends in the semiconductor region between adjacent trenches. A dielectric material fills a bottom portion of each of the gated and non-gated trenches. A gate electrode is disposed in each gated trench. A conductive material of the second conductivity type is disposed in each non-gated trench such that the conductive material and contacts corresponding body regions along sidewalls of the non-gated trench. | 02-27-2014 |
20140073098 | METHOD FOR FORMING A SCHOTTKY BARRIER DIODE INTEGRATED WITH A TRENCH MOSFET - A method for forming a Schottky diode including forming first and second trenches in a semiconductor layer, forming a thin dielectric layer lining sidewalls of the first and second trenches; forming a trench conductor layer in the first and second trenches where the trench conductor layer fills a portion of each of the first and second trenches and being the only one trench conductor layer in the first and second trenches; forming a first dielectric layer in the first and second trenches to fill the remaining portions of the first and second trenches; and forming a Schottky metal layer on a top surface of the lightly doped semiconductor layer between the first trench and the second trench to form a Schottky junction. The Schottky diode is formed with the Schottky metal layer as the anode and the lightly doped semiconductor layer between the first and second trenches as the cathode. | 03-13-2014 |
20140175536 | HIGH DENSITY TRENCH-BASED POWER MOSFETS WITH SELF-ALIGNED ACTIVE CONTACTS AND METHOD FOR MAKING SUCH DEVICES - 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 T | 06-26-2014 |
20140203355 | FIELD EFFECT TRANSISTOR AND SCHOTTKY DIODE STRUCTURES - In accordance with an embodiment a structure can include a monolithically integrated trench field-effect transistor (FET) and Schottky diode. The structure can include a first gate trench extending into a semiconductor region, a second gate trench extending into the semiconductor region, and a source region flanking a side of the first gate trench. The source region can have a substantially triangular shape, and a contact opening extending into the semiconductor region between the first gate trench and the second gate trench. The structure can include a conductor layer disposed in the contact opening to electrically contact the source region along at least a portion of a slanted sidewall of the source region, and the semiconductor region along a bottom portion of the contact opening. The conductor layer can form a Schottky contact with the semiconductor region. | 07-24-2014 |
20140239388 | TERMINATION TRENCH FOR POWER MOSFET APPLICATIONS - Aspects of the present disclosure describe a termination structure for a power MOSFET device. A termination trench may be formed into a semiconductor material and may encircle an active area of the MOSFET. The termination trench may comprise a first and second portion of conductive material. The first and second portions of conductive material are electrically isolated from each other. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. | 08-28-2014 |
20140264571 | SHIELDED GATE TRENCH MOSFET PACKAGE - 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 connected to the source regions and insulated from the gate electrode and shield electrode. The source pad provides an external contact to the source region. A gate pad provides an external contact to the gate electrode. A shield electrode pad provides an external contact to the shield electrode. A resistive element is electrically connected between the shield electrode pad and a source lead. | 09-18-2014 |
20140319605 | NANO MOSFET WITH TRENCH BOTTOM OXIDE SHIELDED AND THIRD DIMENSIONAL P-BODY CONTACT - A semiconductor power device may include a lightly doped layer formed on a heavily doped layer. One or more devices are formed in the lightly doped layer. Each device may include a body region, a source region, and one or more gate electrodes formed in corresponding trenches in the lightly doped region. Each of the trenches has a depth in a first dimension, a width in a second dimension and a length in a third dimension. The body region is of opposite conductivity type to the lightly and heavily doped layers. The source region is formed proximate the upper surface. One or more deep contacts are formed at one or more locations along the third dimension proximate one or more of the trenches. The contacts extend in the first direction from the upper surface into the lightly doped layer and are in electrical contact with the source region. | 10-30-2014 |
20140339630 | DEVICE STRUCTURE AND METHODS OF MAKING HIGH DENSITY MOSFETS FOR LOAD SWITCH AND DC-DC APPLICATIONS - 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 source contacts allow for the production of devices with a pitch in the deep sub-micron level. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. | 11-20-2014 |
20140374824 | MOSFET WITH INTEGRATED SCHOTTKY DIODE - Aspects of the present disclosure describe a Schottky structure with two trenches formed in a semiconductor material. The trenches are spaced apart from each other by a mesa. Each trench may have first and second conductive portions lining the first and second sidewalls. The first and second portions of conductive material are electrically isolated from each other in each trench. The Schottky contact may be formed at any location between the outermost conductive portions. The Schottky structure may be formed in the active area or the termination area of a device die. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. | 12-25-2014 |
20150021682 | NORMALLY ON HIGH VOLTAGE SWITCH - In some embodiments, a normally on high voltage switch device (“normally on switch device”) incorporates a trench gate terminal and buried doped gate region. In other embodiments, a surface gate controlled normally on high voltage switch device is formed with trench structures and incorporates a surface channel controlled by a surface gate electrode. The surface gate controlled normally on switch device may further incorporate a trench gate electrode and a buried doped gate region to deplete the conducting channel to aid in the turning off of the normally on switch device. The normally on switch devices thus constructed can be readily integrated with MOSFET devices and formed using existing high voltage MOSFET fabrication technologies. | 01-22-2015 |