226 results about "LOCOS" patented technology

Electro-Static Discharge (ESD) protection using at least one ring-shape diode is disclosed. The ring-shape diode can be constructed from polysilicon, active region body on insulated substrate, or junction diode on silicon substrate. The diodes can have a first type of implant in an outer ring and a second type of implant in an inner ring to serve as two terminals of a diode coupled through contacts, vias, or metals. The two types of implant ring regions are separated with an isolation structure. The isolation can be LOCOS, STI, dummy gate, or silicide block layer (SBL). The ESD structure has at least a ring-shape diode with a first terminal coupled to an I/O pad and the second terminal coupled to a first supply voltage. The contours of the ring-shape diode can be circles, polygons, or other shapes. The ring-shape ESD structures can be multiple and be constructed in concentric manner.

An Electro-Static Discharge (ESD) protection using at least one I/O pad with at least one mesh structure of diodes provided on a semiconductor body is disclosed. The mesh structure has a plurality of cells. At least one cell can have a first type of implant surrounded by at least one cell with a second type of implant in at least one side of the cell, and at least cell can have a second type of implant surrounded by at least one cell with a first type of implant in at least one side of the cell. The two types of implant regions can be separated with a gap. A silicide block layer (SBL) can cover the gap and overlap into the both implant regions to construct P/N junctions on the polysilicon or active-region body on an insulated substrate. Alternatively, the two types of implant regions can be isolated by LOCOS, STI, dummy gate, or SBL on silicon substrate. The regions with the first and the second type of implants can be coupled to serve as the first and second terminal of a diode, respectively. The mesh structure can have a first terminal coupled to the I/O pad and a first terminal coupled to a first supply voltage.

Fabrication methods for capacitive micromachined ultrasonic transducers (CMUTS) with independent and precise gap and post thickness control are provided. The fabrication methods are based on local oxidation or local oxidation of silicon (LOCOS) to grow oxide posts. The process steps enable low surface roughness to be maintained to allow for direct wafer bonding of the membrane. In addition, methods for fabricating a step in a substrate are provided with reduced or minimal over-etch time by utilizing the nonlinearity of oxide growth. The fabrication methods of the present invention produce CMUTs with unmatched uniformity, low parasitic capacitance, and high breakdown voltage.

A power Schottky rectifier device and method of making the same are disclosed. The Schottky rectifier device includes a LOCOS structure grown on the bottom of the trenches by using nitride spacer on the sidewall of the trenches as a thermal oxidation mask. A polycrystalline silicon layer is then filled the first trenches. Under LOCOS structure, a p doped region is optionally formed to minimize the current leakage when the device undergoes a reverse biased. A Schottky barrier silicide layer formed by sputtering and annealing steps is formed on the upper surfaces of the epi-layer and the polycrystalline silicon layer. A top metal layer served as anode is then formed on the Schottky barrier silicide layer and extended to cover a portion of field oxide region of the termination trench. A metal layer served as a cathode electrode is then formed on the backside surface of the substrate opposite to the top metal layer.

A vertical MOSFET of the present invention comprises a semiconductor wafer having a groove selectively etching in the semiconductor wafer to have substantially vertical side walls. The groove is oxidized using local oxidation of silicon (LOCOS) at 1100.degree. C. or greater to form a LOCOS film on the semiconductor wafer in the groove so that a whole side surface of said semiconductor wafer exposed by the groove is substantially vertical and essentially flat. The LOCOS film in the groove is removed and a thermal insulating film on the semiconductor wafer in the groove. Then a gate electrode made of a conductive film is formed on the thermal insulating film. An interlayer insulating film is formed on the gate electrode and a source electrode is formed in ohmic contact with a source region and a base region. A drain electrode is connected to the opposite side of the semiconductor wafer. As a result, the vertical MOSFET of the present invention has improved on-state resistance, reduced parasitic capacitance and higher breakdown voltage.

The present invention provides a semiconductor substrate, which comprises a singlecrystalline Si substrate which includes an active layer having a channel region, a source region, and a drain region, the singlecrystalline Si substrate including at least a part of a device structure not containing a well-structure or a channel stop region; a gate insulating film formed on the singlecrystalline Si substrate; a gate electrode formed on the gate insulating film; a LOCOS oxide film whose thickness is more than a thickness of the gate insulating film, the LOCOS oxide film being formed on the singlecrystalline Si substrate by surrounding the active layer; and an insulating film formed over the gate electrode and the LOCOS oxide film. On this account, on fabricating the semiconductor device having a high-performance integration system by forming the non-singlecrystalline Si semiconductor element and the singlecrystalline Si semiconductor element on the large insulating substrate, the process for making the singlecrystalline Si is simplified. Further, the foregoing arrangement provides a semiconductor substrate and a fabrication method thereof, which ensures device isolation of the minute singlecrystalline Si semiconductor element without highly-accurate photolithography, when the singlecrystalline Si semiconductor element is transferred onto the large insulating substrate.

A semiconductor power device includes a plurality of trenched gates. The trenched gates include a thin dielectric layer padded sidewalls of the trenched gate and a tub-shaped thick dielectric layer below a bottom of the trenched gates having a width narrower than the trenched gate. In an exemplary embodiment, the tub-shaped thick dielectric layer below a bottom of the trenched gates further includes a local deposition of silicon oxide (LOCOS) filling in a tub-shaped trench having a narrower width than the trenched gate. In another exemplary embodiment, the tub-shaped thick dielectric layer below a bottom of the trenched gates further comprising a high density plasma (HDP) chemical vapor deposition (CVD) silicon oxide filled in a tub-shaped trench having a narrower width than the trenched gate.

The LOCOS-based junction-pinched Schottky rectifier comprises a raised diffusion guard ring surrounded by an outer LOCOS field oxide layer, a raised diffusion grid or a plurality of raised diffusion rings or stripes surrounded by the raised diffusion guard ring, a plurality of recessed semiconductor surfaces formed on a lightly-doped epitaxial semiconductor layer surrounded by the raised diffusion guard ring and the raised diffusion grid or by the raised diffusion guard ring and the plurality of raised diffusion rings or stripes, and a metal silicide layer or a metal layer being at least formed over a portion of the raised diffusion guard ring, the plurality of recessed semiconductor surfaces and the raised diffusion grid or the plurality of raised diffusion rings or stripes. A plurality of compensated diffusion layers can be formed in surface portions of the lightly-doped epitaxial semiconductor layer under the plurality of recessed semiconductor surfaces.

In a semiconductor device including a monocrystalline thin film transistor 16a that has been formed on a monocrystalline Si wafer 100 and then is transferred to a insulating substrate 2, LOCOS oxidization is performed with respect to the element-isolation region of the monocrystalline Si wafer 100 so as to create a field oxide film (SiO₂ film) 104, and a marker 107 is formed on the field oxide film 104. With this structure, alignment of components may be performed based on a gate electrode 106 upon or after the transfer step.

A method for making trench MOSFET with shallow trench structures with thick trench bottom is disclosed. The improved method resolves the problem of deterioration of breakdown voltage resulted by LOCOS having a bird's beak shape introduced in prior art, and at the same time, the inventive device has a lower Qgd and lower Rds.

An object of the present invention is to provide a semiconductor device that is able to realize a low on-resistance maintaining a high drain-to-source breakdown voltage, and a method for manufacturing thereof, the present invention including: a supporting substrate 1; a semiconductor layer 3 having a P⁻ type active region 3a that is formed on the supporting substrate 1, interposing a buried oxide film 2 between the semiconductor layer 3 and the supporting substrate 1; and a gate electrode 16a that is formed on the semiconductor layer 103, interposing a gate oxide film 17 and a part of a LOCOS film 5a between the gate electrode 16a and the semiconductor layer 103, wherein the P⁻ type active region 3a has: an N⁺ type source region 11; a P type body region 12; a P⁺ type back gate contact region 14; an N type drain offset region 19; an N⁺ type drain contact region 20; and an N type drain buffer region 18 that is formed in a limited region between the N type drain offset region 19 and the P type body region 12, and the N type drain buffer region 18 is in contact with a source side end of the LOCOS film 5a and is shallower than the N type drain offset region 19.

The invention provides a method for manufacturing a high-voltage lateral dual-diffusion N-channel metal oxide semiconductor (NMOS) based on a standard complementary metal-oxide-semiconductor transistor (CMOS) process. The method comprises the following steps of: providing a P type silicon substrate, manufacturing local oxidation of silicon (LOCOS) on the P type silicon substrate, and dividing theLOCOS into a low-voltage CMOS area and a high-voltage lateral diffused N-channel metal oxide semiconductor (LDNMOS) area; injecting phosphor into the LDNMOS area and diffusing the phosphor to form a high-voltage N well; performing a two-well process in the CMOS area to form a low-voltage N well and a low-voltage P well; sequentially forming a thick gate oxide layer and a thin gate oxide layer in the LDNMOS area; sequentially forming a polysilicon layer and a silicon nitride layer and sequentially etching the polysilicon layer and the silicon nitride layer to form a grid electrode and a buffering layer respectively; coating a photoresist, and exposing the injection position of a P type area of the LDNMOS area after exposing and development; injecting P type ions for two times at the anglesof more than 30 degrees and less than 7 degrees respectively to form channels of an LDNMOS, wherein the photoresist and the buffering layer serve as masks; and forming source areas and drain areas ofa P-channel metal oxide semiconductor (PMOS) and an NMOS, and contact ends of a source area, a drain area and a P type area of the LDNMOS by taking the grid electrode as an alignment mark. Because a large-angle injection process is used for forming the channels after the grid electrode is formed, a long-time high-temperature heating process is not required and the process is compatible.

The LOCOS-based Schottky barrier diode of the present invention comprises a raised diffusion guard ring surrounded by an outer LOCOS field oxide layer, a recessed semiconductor substrate with or without a compensated diffusion layer surrounded by the raised diffusion guard ring, a metal silicide layer formed over a portion of the raised diffusion guard ring and the recessed semiconductor substrate, and a patterned metal layer formed at least over the metal silicide layer, wherein the raised diffusion guard ring is formed between an inner LOCOS field oxide layer and the outer LOCOS field oxide layer and the recessed semiconductor substrate is formed by removing the inner LOCOS field oxide layer. The LOCOS-based Schottky barrier diode comprises the raised diffusion guard ring to reduce junction curvature effect on reverse breakdown voltage, the recessed semiconductor substrate to reduce forward voltage, and the compensated diffusion layer to reduce reverse leakage current.

A semiconductor device includes a substrate including a high-voltage transistor area provided with a high-voltage transistor and a low-voltage transistor area provided with a low-voltage transistor; a LOCOS layer provided as a device isolation layer of the high-voltage transistor area; and a shallow-trench isolation layer provided as a device isolation layer of the low-voltage transistor area. Accordingly, a sufficient breakdown voltage level can be provided in a high-voltage transistor area, on-resistance and leakage current can be enhanced, and the chip area in a low-voltage transistor area can be reduced.