141results about How to "Reduce gate-to-drain capacitance" patented technology

In a trench MOSFET, the lower portion of the trench contains a buried source electrode, which is insulated from the epitaxial layer and semiconductor substrate but in electrical contact with the source region. When the MOSFET is in an “off” condition, the bias of the buried source electrode causes the “drift” region of the mesa to become depleted, enhancing the ability of the MOSFET to block current. The doping concentration of the drift region can therefore be increased, reducing the on-resistance of the MOSFET. The buried source electrode also reduces the gate-to-drain capacitance of the MOSFET, improving the ability of the MOSFET to operate at high frequencies. The substrate may advantageously include a plurality of annular trenches separated by annular mesas and a gate metal layer that extends outward from a central region in a plurality of gate metal legs separated by source metal regions.

In a trench MOSFET, the lower portion of the trench contains a buried source electrode, which is insulated from the epitaxial layer and semiconductor substrate but in electrical contact with the source region. When the MOSFET is in an “off” condition, the bias of the buried source electrode causes the “drift” region of the mesa to become depleted, enhancing the ability of the MOSFET to block current. The doping concentration of the drift region can therefore be increased, reducing the on-resistance of the MOSFET. The buried source electrode also reduces the gate-to-drain capacitance of the MOSFET, improving the ability of the MOSFET to operate at high frequencies. The substrate may advantageously include a plurality of annular trenches separated by annular mesas and a gate metal layer that extends outward from a central region in a plurality of gate metal legs separated by source metal regions.

This invention discloses a semiconductor power device that includes a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate. At least one active cell further includes a trenched source contact opened between the trenches wherein the trenched source contact opened through a source region into a body region for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of the trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell. A shielding structure is disposed at the bottom and insulated from the trenched gate to provide shielding effect for both the trenched gate and the Schottky diode.

A “chained implant” technique forms a body region in a trench gated transistor. In one embodiment, a succession of “chained” implants can be performed at the same dose but different energies. In other embodiments different doses and energies can be used, and particularly, more than one dose can be used in a single device. This process produces a uniform body doping concentration and a steeper concentration gradient (at the body-drain junction), with a higher total body charge for a given threshold voltage, thereby reducing the vulnerability of the device to punchthrough breakdown. Additionally, the source-body junction does not, to a first order, affect the threshold voltage of the device, as it does in DMOS devices formed with conventional diffused body processes.

A finFET block architecture uses end-to-end finFET blocks in which the fin lengths are at least twice the contact pitch, whereby there is enough space for interlayer connectors to be placed on the proximal end and the distal end of a given semiconductor fin, and on the gate element on the given semiconductor fin. A first set of semiconductor fins having a first conductivity type and a second set of semiconductor fins having a second conductivity type can be aligned end-to-end. Interlayer connectors can be aligned over corresponding semiconductor fins which connect to gate elements.

An orthogonal gate extended drain MOSFET (EDMOS) structure provides a low gate-to-drain capacitance (CGD) and exhibits increased reliability. It has a gate electrode that is folded into the shallow trench isolation (STI) oxide region. Horizontal and vertical gate electrode segments provide gate control. It accommodates both high voltage devices and standard CMOS components on the same substrate. Reduced surface field (RESURF) technology is employed to optimize tradeoffs between high breakdown voltage and specific on-resistance. Device fabrication steps are compatible with standard CMOS flow and process modules can be added or removed from baseline CMOS technology.

A trenched semiconductor power device includes a plurality of trenched gates surrounded by source regions near a top surface of a semiconductor substrate encompassed in body regions. The trenched semiconductor power device further comprises tilt-angle implanted body dopant regions surrounding a lower portion of trench sidewalls for reducing a gate-to-drain coupling charges Qgd between the trenched gates and a drain disposed at a bottom of the semiconductor substrate. The trenched semiconductor power device further includes a source dopant region disposed below a bottom surface of the trenched gates for functioning as a current path between the drain to the source for preventing a resistance increase caused by the body dopant regions surrounding the lower portions of the trench sidewalls.

This invention discloses a semiconductor power device that includes a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate. At least one of the cells constituting an active cell has a source region disposed next to a trenched gate electrically connecting to a gate pad and surrounding the cell. The trenched gate further has a bottom-shielding electrode filled with a gate material disposed below and insulated from the trenched gate. At least one of the cells constituting a source-contacting cell surrounded by the trench with a portion functioning as a source connecting trench is filled with the gate material for electrically connecting between the bottom-shielding electrode and a source metal disposed directly on top of the source connecting trench. The semiconductor power device further includes an insulation protective layer disposed on top of the semiconductor power device having a plurality of source openings on top of the source region and the source connecting trench provided for electrically connecting to the source metal and at least a gate opening provided for electrically connecting the gate pad to the trenched gate.

The invention discloses a shield gate trench MOSFET. The gate trench includes a top trench and a bottom trench. A polysilicon gate is formed on both sides of the top trench. Source polysilicon is located in the middle of the gate trench and extends longitudinally through the entire gate trench. Channel regions are formed on semiconductor substrate surfaces between gate structures and source regions are formed on the surfaces of the channel regions. A polysilicon gate on one side of the top trench is connected to a gate formed by a front metal layer. A polysilicon gate on the other side of the top trench and the source regions are connected to a source through a second contact hole to form a structure for reducing the gate-drain capacitance of a device. The second contact hole reduces the distance between the gate trenches and reduces the on-resistance of the device and form an on-resistance compensation structure. The invention also discloses a method for manufacturing the shield gate trench MOSFET. The shield gate trench MOSFET can reduce the gate-drain capacitance, can increase the switching speed of the device, and can reduce the size of a unit device and improve an integration level.

A process for manufacturing a trench MIS device includes depositing a conformal nitride layer in the trench; etching the nitride layer to create an exposed area at the bottom of the trench; and heating the substrate and thereby growing an oxide layer in the exposed area. This process causes the mask layer to “lift off”, creating a “bird's beak” structure. This becomes a “transition region”, where the thickness of the oxide layer decreases gradually in a direction away from the exposed area. The method further includes diffusing a dopant into the substrate, the dopant forming a PN junction with a remaining portion of said substrate, and controlling the diffusion such that the PN junction intersects the trench in the transition region. Because the thickness of the oxide layer decreases gradually, the PN junction does not need to be located at a particular point, i.e., there is a margin of error. This improves the manufacturability of the device and enhances its breakdown characteristics.

This invention discloses a method for manufacturing a trenched semiconductor power device that includes step of opening a trench in a semiconductor substrate. The method further includes a step of opening a top portion of the trench first then depositing a SiN on sidewalls of the top portion followed by etching a bottom surface of the top portion of the trench then silicon etching to open a bottom portion of the trench with a slightly smaller width than the top portion of the trench. The method further includes a step of growing a thick oxide layer along sidewalls of the bottom portion of the trench thus forming a bird-beak shaped layer at an interface point between the top portion and bottom portion of the trench.

Trench MOSFETs including active corner regions and a thick insulative layer at the bottom of the trench are disclosed, along with methods of fabricating such MOSFETs. In an exemplary embodiment, the trench MOSFET includes a thick insulative layer centrally located at the bottom of the trench. A thin gate insulative layer lines the sidewall and a peripheral portion of the bottom surface of the trench. A gate fills the trench, adjacent to the gate insulative layer. The gate is adjacent to the sides and top of the thick insulative layer. The thick insulative layer separates the gate from the drain conductive region at the bottom of the trench yielding a reduced gate-to-drain capacitance making such MOSFETs suitable for high frequency applications.

The present invention provides a shield grid DMOS device, belonging to the technical field of power semiconductors. An extra floating grid electrode is arranged between a control grid electrode and ashield grid electrode, dielectric layers are configured to mutually isolate the electrodes, the floating grid electrode with an adjustable position is introduced, the grid source capacitance of the device is reduced, the specific value of the grid source capacitance and the grid-drain capacitance is adjustable, and the combination of the floating grid electrode and the earthed shield grid electrode allows an electric field in a first conductive type semiconductor drift region to be more uniformly distributed. The shield grid DMOS device reduces the switching loss of the device, improves the device switching speed and voltage withstand level and improves the contradictory relation of the conduction resistance and the switching loss.

A trenched semiconductor power device includes a plurality of trenched gates surrounded by source regions near a top surface of a semiconductor substrate encompassed in body regions. The trenched semiconductor power device further comprises tilt-angle implanted body dopant regions surrounding a lower portion of trench sidewalls for reducing a gate-to-drain coupling charges Qgd between the trenched gates and a drain disposed at a bottom of the semiconductor substrate. The trenched semiconductor power device further includes a source dopant region disposed below a bottom surface of the trenched gates for functioning as a current path between the drain to the source for preventing a resistance increase caused by the body dopant regions surrounding the lower portions of the trench sidewalls.

This invention discloses a method of manufacturing a trenched semiconductor power device with split gate filling a trench opened in a semiconductor substrate wherein the split gate is separated by an inter-poly insulation layer disposed between a top and a bottom gate segments. The method further includes a step of forming the inter-poly layer by applying a RTP process after a HDP oxide deposition process to bring an etch rate of the HDP oxide layer close to an etch rate of a thermal oxide.

This invention discloses a trenched semiconductor power device that includes a trenched gate surrounded by a source region encompassed in a body region above a drain region disposed on a bottom surface of a substrate. The trenched gate further includes at least two mutually insulated trench-filling segments with a bottom insulation layer surrounding a bottom trench-filling segment having a bird-beak shaped layer on a top portion of the bottom insulation attached to sidewalls of the trench extending above a top surface of the bottom trench-filling segment.

The invention belongs to the field of power semiconductor devices, and relates to a lateral three-gate power LDMOS based on a bulk silicon technology. The three-gate power LDMOS is mainly characterized by having a three-gate structure and a second conductive material electrically connected with a source or a gate or an external electrode. The three-gate power LDMOS has the main advantages that the three-gate structure increases the channel density and reduces the channel resistance, and thus, the specific on-resistance drops; the second conductive material can freely select the electrode, when the gate electrode is connected, in the positive case, electron accumulation surfaces are formed on the side surface and the bottom surface of a second groove, a multi-dimension low-resistance channel is formed, and the specific on-resistance is greatly reduced, and in the reverse case, assistant depletion of a drift region is carried out, the drift area doping concentration of the device is increased, the specific on-resistance of the device is reduced; when the source electrode is connected, gate-drain overlapping is reduced, the gate-drain capacitance of the device is reduced, and switching loss is reduced; and when the external electrode is electrically connected, multiple effects can be achieved.

This invention discloses an improved trenched metal oxide semiconductor field effect transistor (MOSFET) device that includes a trenched gate surrounded by a source region encompassed in a body region above a drain region disposed on a bottom surface of a substrate. The MOSFET cell further includes a shielded gate trench (SGT) structure below and insulated from the trenched gate. The SGT structure is formed substantially as a round hole having a lateral expansion extended beyond the trench gate and covered by a dielectric liner layer filled with a trenched gate material. The round hole is formed by an isotropic etch at the bottom of the trenched gate and is insulated from the trenched gate by an oxide insulation layer. The round hole has a lateral expansion beyond the trench walls and the lateral expansion serves as a vertical alignment landmark for controlling the depth of the trenched gate. The MOSFET device has a reduced gate to drain capacitance Cgd depending on the controllable depth of the trenched gate disposed above the SGT structure formed as a round hole below the trenched gate.