Abstract: Prior to a heat treatment for bonding a III-V group compound semiconductor layer on a silicon substrate, a thermal stress relaxation layer is provided between the silicon layer and the III-V group compound semiconductor layer thermal stress relaxation layer, having a thermal expansion coefficient equal or near to the thermal expansion coefficient of the III-V group compound semiconductor layer and having a rigidity coefficient being sufficiently large to suppress generation of any crystal defects in the III-V group compound semiconductor layer due to a thermal stress generated in the heat treatment and subsequent cooling stage by the difference in the thermal expansion coefficient between the III-V group compound semiconductor layer and the silicon layer.

Abstract: A method and apparatus for creating unique gemstones is provided. The method comprises the steps of optically contacting the gemstones of interest followed by a heat treatment of the composite gemstone. The heat treatment step increases the bond strength and therefore the resistance of the bond to reversal. In one aspect of the invention, a composite gem is fabricated by bonding a naturally occurring gem to an artificial gem to form a single composite gemstone of large size that outwardly appears to be a single natural gem. The composite gem may be fabricated at a fraction of the cost of a natural stone of the same size. In another aspect of the invention, an intensely colored natural stone is bonded to a colorless or lightly colored artificial stone. This composite retains the intense color associated with the natural stone while enjoying the brilliance, depth, and size resulting from the combination of stones.

Abstract: A method for the releasable bonding of at least two wafers (10, 12), for example of two silicon wafers (silicon discs), or of a silicon wafer and a glass wafer, or of a semiconductor wafer and a cover wafer, by a wafer bonding method in which the surfaces to be brought into contact with one another are at least substantially optically smooth and flat. Prior to bringing the surfaces of the wafers (10, 12) into contact, one or more drops of a liquid are applied to at least one of the surfaces, and the wafer bonding method is carried out at least substantially at room temperature, or at a somewhat higher temperature, or optionally at a somewhat lower temperature. The wafers (10, 12) which are bonded together can easily be separated from one another in that at least the liquid enclosed between the wafers (10, 12), which are bonded to one another, is exposed to a temperature lying substantially above the bonding temperature at which the liquid vaporizes. A wafer structure is also disclosed.

Abstract: An SOI substrate and a method for fabricating the same are provided to sharpen the departing angle at the circumference of the active substrate, and provide the active substrate with a uniform thickness. An attached wafer of the present invention is formed by processing the upper side of the base substrate so that its thickness increases from the center to the circumference, and attaching the active substrate to the processed side of the base substrate. The unattached portion of the attached wafer is removed. Then mirror processing is performed to provide the active substrate with a substantially uniform thickness along the processed side of the base substrate.

Abstract: Proposed is an improvement in the process for the preparation of an SOI wafer comprising the steps of: forming an oxidized surface film on the mirror-polished surface of a first mirror-polished semiconductor silicon wafer as the base wafer; forming a doped layer with a dopant in a high concentration on the mirror-polished surface of a second mirror-polished semiconductor silicon wafer as the bond wafer; bringing the base wafer and the bond wafer into contact each with the other at the oxidized surface film and the doped layer; and subjecting the thus contacted semiconductor silicon wafers to a heat treatment to effect integral bonding thereof into a precursor of an SOI wafer. The improvement of the invention is accomplished by polishing the surface of the doped layer on the bond wafer before the base wafer and the bond wafer are joined by contacting at the oxidized surface film and the doped layer so that a great improvement can be obtained in the bonding strength between layers.

Abstract: A process for integrating a vertical power device, such as an IGBT device, with suitable control circuitry, such as circuitry that provides self-protection from over-temperature (OT), over-voltage (OV) and over-current (OC) conditions. The process yields a vertical power device that is monolithically integrated with, and dielectrically isolated from, its control circuitry with the use of wafer-bonded silicon-on-insulator (SOI) material that yields a buried oxide layer. The process includes simultaneous fabrication of the power device below the buried oxide layer and its control circuitry above the buried oxide layer, in the SOI layer.

Abstract: A method of manufacturing a joined-type semiconductor device having a gate structure. The semiconductor device includes a first and second semiconductor substrates each having a substrate body, and a first and a second main surfaces which are opposite to each other. A gate structure is formed in the first main surface of the first substrate. A highly-doped semiconductor layer is formed in the first main surface of the second substrate and has an impurity-concentration which is higher than that of the substrate body of the second substrate. The first main surfaces of the two substrates are joined with each other, by subjecting the two substrates to a heat treatment so that impurities in the highly-doped semiconductor layer of the second substrate are driven into the surface region of the first substrate, and a diffusion layer is thereby formed in the first main surface of the first substrate.

Abstract: A single-etch stop process for the manufacture of silicon-on-insulator wafers. The process includes forming a silicon-on-insulator bonded wafers comprising a substrate layer, an oxide layer, a device layer, and a device wafer. The device layer is situated between the device wafer and the oxide layer and the oxide layer is between the device layer and the substrate layer. The device wafer has a p.sup.+ or n.sup.+ conductivity type and a resistivity ranging from about 0.005 ohm-cm to about 0.1 ohm-cm. A portion of the device wafer is removed from the silicon-on-insulator bonded wafers and the remaining portion of the device wafer has a defect-free surface after such removal. The remaining portion of the device wafer is then etched to expose the device layer.

Abstract: A method of direct-bonding semiconductor wafers limits the time interval between a bonding step and a bonding anneal step or performs a baking step between the bonding and bonding anneal steps at a predetermined temperature for a predetermined time interval to prevent the formulation of voids on the edge regions of the wafers. The method for fabricating laminated semiconductor wafers includes a bonding step to fit together two polished semiconductor wafers by bonding jigs, and a succeeding bonding anneal step to laminate the wafers. In the method the bonding anneal step is preferably carried out within an hour following the bonding step; or a baking step at a predetermined temperature for a predetermined time interval is carried out between the bonding step and the bonding anneal step. Further, the method can prevent heavy metal impurities attached to the surface of the wafer from diffusing into the wafer by baking the wafer for over 5 minutes at above 100.degree. C.

Abstract: A buried silicide layer 111 in a bonded wafer 105 makes ohmic contact to a heavily doped buried layer 125. A dopant rapidly diffuses through the silicide layer and into the adjacent semiconductor to form the buried layer.

Abstract: A reduced size, hermetically sealed semiconductor transducer and methods for fabricating the same. In a preferred embodiment, the transducer comprises a transducer wafer including a diaphragm which deflects upon the application of a force thereto. At least one semiconductor transducer element and one electrical contact are disposed on a top surface of the transducer wafer, with the electrical contact coupled to the semiconductor element and extending to a peripheral portion of the wafer. A cover member is provided that is dimensioned to surround the semiconductor element. A peripheral glass frit bond is formed between the cover member and the transducer wafer, and between the cover member and at least a portion of the electrical contact. An aperture is formed in a top portion of the cover member, positioned above a region bounded by the peripheral glass bond. This aperture functions to prevent air gap formation in the peripheral glass frit bond.

Abstract: A process is provided for protecting, containing, and/or completing fragile microelectronic and microelectromechanical (MEM) structures on a low conductivity substrate during anodic wafer bonding of a covering wafer. The wafer includes raised areas that contact the substrate at selected bonding regions to support the wafer as a covering structure over the substrate. The covering wafer includes additional raised areas, such as pillars or posts, that contact selected electric circuit lines on the substrate to form temporary shorts through the wafer. During anodic bonding of the wafer to the substrate, the temporary shorts maintain the connected circuit lines and microstructures at nearly the same electric potential to prevent unwanted arcing and electrostatic forces that could damage the fragile structures. The pillars or posts can be formed at the same time as the raised bonding areas, but on unwanted and otherwise unused portions of the covering wafer.

Abstract: The present invention provides an interconnect system. The interconnect system includes a substrate, a first dielectric layer deposited upon the substrate. The interconnect system further includes at least two electrically conductive interconnect lines formed upon the first dielectric layer. Each of the at least two interconnect lines have a top surface and side surfaces. Adjacent side surfaces of two adjacent interconnect lines define therebetween a space that has a dielectric constant substantially equal to 1. A dielectric film is bonded upon the top surface of the at least two interconnect lines. The dielectric film substantially prevents obstruction of the space by further process.

Abstract: Low temperature wafer bonding using a chemically reacting material between wafers to form a bonded zone to bond two wafers together. Examples include silicon wafers with a silicon-oxidizing bonding liquid which also permits introduction of radiation hardening dopants and electrically active dopants as constituents of the bonding liquid. Silicon wafers also may use solid reactants which include deposited layers of metal and polysilicon to form silicide bonded zones. Oxidizers such as nitric acid may be used in the bonding liquid, and a bonding liquid may be used in conjunction with a solid bonding reactant. Dielectric layers on silicon wafers may be used when additional silicon is provided for the bonding reactions. Integrated circuits fabricated from such bonded wafers may have buried layers and radiation hardening and buried resistors.

Abstract: A method of forming defect-free permanent bonds without the use of adhesives as well as devices formed by this method is disclosed. In general, the disclosed process allows similar or dissimilar crystalline, vitreous or dense polycrystalline ceramic, metallic or organic polymeric components to be first joined by optical contacting and then heat treated to stabilize the bond. The heat treatment can be performed at a low enough temperature to prevent interdiffusion between species, thus insuring that the bond is not subjected to excessive mechanical stresses and that the materials do not undergo phase changes.

Abstract: A method of fabricating a bonded wafer which is capable of reducing the concentrations of impurities, and more particularly the boron concentration, at the interface of bonding in the bonded wafer, wherein first and second wafers to be bonded are finish-cleaned, then the wafers are temporarily stored in a closed box so as to isolate the wafers from clean-room air, thereafter the first and second wafers are superposed in a clean atmosphere which is held out of direct contact with clean-room air, and finally the superposed first and second wafers are bonded together by a heat-treatment.

Abstract: Warpage in a bonded wafer is limited by maintenance of a stress compensation layer on the backside of the bonded wafer during device fabrication processing. One embodiment applies a sacrificial polysilicon layer over a stress compensation silicon dioxide layer for bonded silicon wafers. The fabrication processing consumes the polysilicon layer but not the stress compensation silicon dioxide.

Abstract: A semiconductor substrate includes a semiconductor layer, where the density of an impurity is reduced by out diffusion, provided on an insulating layer. In a method for manufacturing such a semiconductor substrate, a semiconductor substrate including a high-density impurity layer at the side of its surface is bonded to another substrate having an insulating layer. Thereafter, the semiconductor substrate is removed, and the impurity density of the remaining high-density impurity layer is reduced by out diffusion.

Abstract: A method of wafer bonding with less elongation and contraction of wafers at the time of and after the bonding of the wafers is disclosed. In the method of wafer bonding, wafers are bonded together with sticking force of their surfaces to form a bonded wafer. The bonding is done by selecting the pressure of the gas between the wafers to be lower than the atmospheric pressure, for instance, and also selecting the kind of gas between the wafers to H.sub.2, for instance.

Abstract: A semiconductor substrate comprises a plurality of substrates to be bonded, wherein a bond promotion layer into which silicon atoms are implanted is provided in an interface between the substrates to be bonded, and the substrates are bonded to each other with the interposition of the bond promotion layer.

Abstract: A process for manufacturing a light valve device comprises forming a transparent insulating thin film layer on a surface of a semiconductor substrate, and forming a single crystal semiconductor thin film on a surface of the transparent insulating thin film layer. A portion of the single crystal semiconductor thin film is then removed and at least one pixel electrode is formed on the transparent insulating thin film layer at a region where the single crystal semiconductor thin film has been removed. A driving unit is then formed in the single crystal semiconductor thin film. Thereafter, a carrier substrate is laminated using an adhesive on the surface of the semiconductor substrate at a region corresponding to the pixel electrode and the driving unit. The semiconductor substrate is then removed to expose a surface of the transparent insulating thin film layer and through-holes and a metal film are formed on the exposed surface thereof.

Abstract: A first region of a seed substrate is separated from a bonded handle substrate by etching and/or fracturing a second region of the seed substrate. A third region of the seed substrate remains bonded to the handle wafer. Etching and etch ant distribution are facilitated by capillary action in trenches formed in the seed substrate prior to bonding of the handle substrate. A portion of the second region may be removed by undercut etching prior to handle bonding. Elevated pressure and etchant composition are used to suppress bubble formation during etching. Alternatively, pressure from bubble formation is used to fracture a portion of the second region. First, second, and third regions are defined by a variety of methods.

Abstract: A SOI substrate fabricating method comprises the steps of: making a first etch-stop layer on a silicon substrate; polishing the surface of the first etch-stop layer; making a silicon buffer layer on the polished surface of the first etch-stop layer; making a silicon layer on the silicon buffer layer; making an insulating layer on the silicon layer; bonding one of major surfaces of a support substrate onto the insulating layer; and removing the silicon substrate, the first etch-stop layer and the silicon buffer layer and maintaining the insulating layer and the silicon layer on the one surface of the support substrate.

Abstract: A method of manufacturing a composite substrate and the composite substrate manufactured thereby wherein surfaces of first and second substrates having different thermal expansion coefficients are mirror finished and layered on each other. A first heat treatment is applied after which a part of the second substrate is removed to a depth sufficient to expose the first substrate. A final second heat treatment directly bonds the substrates.

Abstract: A process for the laminar joining of two or more silicon semiconductor slices (wafers) under the effect of pressure and heat, in which a thin layer of a semiconductor-compatible material is applied to at least one of the surfaces to be joined.

Abstract: A first silicon single crystal substrate and a second silicon single crystal substrate are bonded together and the first silicon single crystal substrate is formed thin as an SOI layer. An insulation film is buried in portions of the bonding surface of one of the two silicon single crystal substrates, and in addition, a polycrystal silicon layer is formed on the bonding surface of the silicon single crystal substrate on the side into which the insulation film is buried.

Abstract: A method is set forth of manufacturing a silicon body (5) having an n-type top layer (1') and an adjoining, more highly doped n-type base layer (2'), by which a first, n-type silicon slice (1) and a second, more highly doped n-type silicon slice (2) are put one on the other and then bonded together by heating. To obtain a low contact resistance between top layer (1') and base layer (2'), a boundary layer having a higher doping than the to player (1') is provided in the top layer (1') adjoining the base layer (2'). According to the invention, the boundary layer is formed by diffusion of an n-type dopant (11, 14) into the first slice (1) from the second slice (2) during heating. The concentration of the n-type dopant (11, 14) is taken to be so high in this case that boron (12) present as an impurity is overdoped, so that undesired pn transitions cannot occur.

Abstract: In a method for producing a diode, a first, strongly positively doped silicon wafer is bonded in accordance with the silicon fusion method to a second, weakly negatively doped silicon wafer, and subsequently the weakly negatively doped second silicon wafer is ground down to a predetermined thickness. A chromium layer which contains a small percentage of arsenic is used for resistive contact-making on the negatively doped second silicon wafer. In this way, a diode is obtained which has a small forward voltage in conjunction with a precise breakdown voltage.

Abstract: An anodic bonding method allows uniform pressure on the components to be bonded. This is achieved in that the components which are bonded are structured such that cavities are formed between the components. The cavities are evacuated and the components are thus pressed together during bonding.

Abstract: A method of forming a SOI device layer on an oxide layer on top of a substrate is disclosed. The process involves using a device substrate of a first conductivity having a top device layer of a second conductivity. Optionally, a thin layer of silicon dioxide is formed on top of the device layer. A carrier substrate is selected with a surface layer of silicon dioxide. Patterns are etched into the device and carrier substrates to preselected depths and surface widths, in a roughly complementary manner. The etched surfaces present a slope which enables the easy assembly of the device substrate and carrier substrate, the depths of the complementary patterns are controlled by the dopant layer thickness, and the slopes of etched profile are determined by the crystallographic orientations of the silicon substrate. The device substrate is thinned away to leave the device layer over the carrier substrate, thereby forming a device layer on the carrier substrate, separated by a silicon dioxide layer.

Abstract: Bulk crystalline silicon wafers are transferred after the completion of circuit fabrication to form thin films of crystalline circuitry on almost any support, such as metal, semiconductor, plastic, polymer, glass, wood, and paper. In particular, this technique is suitable to form silicon-on-insulator (SOI) wafers, whereby the devices and circuits formed exhibit superior performance after transfer due to the removal of the silicon substrate. The added cost of the transfer process to conventional silicon fabrication is insignificant. No epitaxial, lift-off, release or buried oxide layers are needed to perform the transfer of single or multiple wafers onto support members. The transfer process may be performed at temperatures of 50.degree. C. or less, permits transparency around the circuits and does not require post-transfer patterning.

Abstract: The invention provides a semi-conductor light valve device and a process for fabricating the same. The device comprises a composite substrate having a supporte substrate, a light-shielding thin film formed on said supporte substrate and semiconductive thin film disposed on the light-shielding thin film with interposing an insulating thin film. A switching element made of a transistor and a transparent electrode for driving light valve are formed on the semiconductive thin film, and the switching element and the transparent electrode are connected electrically with each other. The transistor includes a channel region in the semiconductive thin film and a main gate electrode for controlling the conduction in the channel region, and the light-shielding thin film layer is so formed as to cover the channel region on the side opposite to said channel region, so as to prevent effectively a back channel and shut off the incident light.

Abstract: A process for stripping the outer edge of a bonded BESOI wafer. The bonded BESOI wafer comprises a handle wafer, an oxide layer on one surface of the handle wafer, a device layer bonded to the oxide layer, and a p.sup.+ etch-stop layer on the device layer having an exposed face. The process comprises masking the exposed face of the p.sup.+ etch-stop layer, and abrading the periphery of the BESOI wafer to remove edge margins of the p.sup.+ etch-stop layer and device layer.

Abstract: A multi-channel type intelligent power IC which solves the problems of parasitic transistor and increase in an area of isolation region, both of which are inherent problem in a pn junction isolation substrate. The power IC also enhances heat-radiation performance. An n type first semiconductor substrate and p type second semiconductor substrate are directly bonded, and a buried oxide film is formed in a portion of a bonding interface thereof. Subsequently, a plurality of isolation trenches are formed and the first semiconductor substrate is separated into an SOI isolation region and a pn isolation region. Logic elements are then formed in the SOI isolation region, and power elements are formed in the pn isolation region. In the case wherein two or more logic elements are hereby formed, the logic elements are isolated by isolation trenches. In the case wherein two or more power elements are formed, a parasitic current extracting portion is formed between mutual power elements.

Abstract: SOI (silicon-on-insulator) substrates are efficiently produced by a method which comprises superposing and bonding at least three single crystal silicon wafers through the medium of a SiO.sub.2 film formed on the surface of each of the wafers and cutting the bonded wafers along planes perpendicular to the direction of superposition thereof. The cutting can be infallibly attained with high dimensional accuracy without entailing such adverse phenomena as the vibration of the blade of a cutting tool by providing at the portions destined to be cut the grooves for guiding the blade of the cutting tool in advance of the cutting work.

Abstract: The following steps are performed when processing electronic components such as piezoelectric devices. At Step 1 inter-atom bond is created between a functional member such as a quartz crystal plate and a first substrate, and the functional member and the quartz crystal plate are directly joined together. At Step 2, the functional member and a second substrate are fixed together with an adhesive agent or by a direct bond. At Step 3, the first substrate is removed chemically or mechanically, with said functional member and said second substrate still being joined together. A step of polishing said functional member for the adjustment of thickness thereof may be done between Step 1 and Step 2. For example, a silicon dioxide thin film may be provided between the functional member and the first substrate. Since no adhesive layer exists between the functional member and the first substrate, this improves the degree of plane of the functional member when joined to the first substrate.

Abstract: A surface mountable integrated circuit and a method of manufacture are disclosed. A wafer 110 has a die with an integrated circuit 119 in one surface of the wafer. A via 130 extends to the opposite surface. The via has a sidewall oxide 131 and is filled with a conductive material such as metal or doped polysilicon. The metal may comprise a barrier layer and an adhesion layer. The second end of the via can be fashioned as a prong 233 or a receptacle 430. Dies with vias can be stacked on top of each other or surface mounted to printed circuit boards or other substrate.

Abstract: A buried silicide layer 111 in a bonded wafer 105 makes ohmic contact to a heavily doped buried layer 125. A dopant rapidly diffuses through the silicide layer and into the adjacent semiconductor to form the buried layer.

Abstract: A process for manufacturing integrated circuits includes the following steps. First, an oxide layer is formed on at least one surface of two respective semiconductor material wafers. Next, a single semiconductor material wafer is obtained with a first layer and a second layer of semiconductor material and a buried oxide layer interposed therebetween starting from said two semiconductor material wafers by direct bonding of the oxide layers previously grown. The single wafer is submitted to a controlled reduction of the thickness of the first layer of semiconductor material and the top surface of the first layer of semiconductor material is lapped. Dopant impurities are selectively introduced into selected regions of the first layer of semiconductor material to form the desired integrated components.

Abstract: A bonded wafer with a bond junction having low resistivity due to the low level of oxides at the bond junction. A plasma that removes native oxide layers from wafers is exposed to the wafers. The plasma forms a hydrophobic polymer seal on the wafers, inhibiting subsequent native oxide growth upon exposure to air. The polymer seal on the wafers to be bonded are pressed together and the wafers are annealed to form the bonded wafer in a non-oxidizing ambient. The bond junction formed is primarily silicon to silicon and silicon to carbon bonds.

Abstract: A method of separating wafers, such as those used for semiconductor device manufacture, into die. A partly fabricated wafer is covered with a protective coating over its top surface (10). The wafer is then inscribed to define separation lines between die, with the separation lines being of a predetermined depth (12). The protective coating is then removed (14), and at least one processing step is performed at the wafer level (15, 22-24), before the inscribed wafer is separated into die. Then, the wafer is separated into die along the separation lines (17).

Abstract: A method of manufacturing a semiconductor device includes the following steps. A silicon oxide film having a predetermined film thickness is formed on a smooth major surface of a first silicon substrate of a first conductivity type having a first region wherein a power transistor is to be formed. The major surface of the first silicon substrate is bonded to a smooth major surface of a second silicon substrate having one of the first conductivity type and a second conductivity type. The other surface of the second silicon substrate bonded to the first silicon substrate is polished to form a silicon layer having a predetermined film thickness and a second region wherein a transistor constituting a control circuit for driving the power transistor is to be formed. The silicon layer and the silicon oxide film are removed from a predetermined portion in the first region.

Abstract: This invention relates to a method for making sealed cavities on silicon wafer surfaces by anodic bonding and with electrically insulated conductors through the sealing areas to connect functional devices inside the cavities to electrical terminals outside said cavities. Said conductors are provided by the use of doped buried crossings in a single crystal silicon substrate, thereby also allowing different kinds of integrated silicon devices, e.g. sensors to be made. Further, the invention relates to a device made by the novel method.

Abstract: A semiconductor wafer is comprised of a transparent layer interposed between a thin silicon layer and a thick silicon layer. Silicon islands are formed from the thin silicon layer on the transparent layer. Device elements are formed in the silicon islands. Thereafter, the thick silicon layer which is a support layer is etched away to form a transparent region on the wafer. The wafer is constructed to avoid elimination or destruction of the transparent layer during the course of formation of the silicon islands and during the course of etching of the rear thick silicon plate. The transparent layer is comprised of a silicon nitride film or a silicon carbide film. Alternatively, the transparent layer is comprised of a silicon oxide film covered by a silicon nitride film or a silicon carbide film on one or both of the upper and lower faces of the silicon oxide film.

Abstract: A method of making a monolithic structure for an optocoupler that provides improved linearity. The method includes forming an output signal photodiode and a feedback control signal photodiode on a single chip with an LED. The photodiodes are configured and positioned relative to the LED to compensate for any non-uniformities in the light received from the LED.

Abstract: A silicon-on-insulator (SOI) gate-all-around (GAA) metal-oxide-semiconductor field-effect transistor (MOSFET) includes a source, channel and drain surrounded by a top gate and a buried bottom gate, the latter of which also has application for other buried structures and is formed on a bottom gate dielectric which was formed on source, channel and drain semiconductor layer of an SOI wafer. After forming a planar bottom insulator layer on the bottom gate and bottom gate dielectric, the SOI wafer is flip-bonded onto an oxide layer of a bulk silicon wafer, thereby encapsulating the buried bottom gate electrode in insulating oxide, after which the SOI substrate and the etch-stop SOI oxide layer are removed to expose the SOI semiconductor layer which is processed to form the source, drain and channel in a mesa structure on which is deposited a top gate dielectric, a top gate, and top gate insulator as well as four conductors for connecting to the source, drain, top gate and bottom gate.

Abstract: A method for manufacturing a silicon bonded wafer includes the steps of preparing a first substrate of a lightly doped N-silicon having a plurality of V-grooves, preparing a second substrate of a heavily doped N-silicon having a first portion covered by an insulating film and a second portion having a top surface flush with the surface of the insulating film, bonding the first and the second substrates such that the V-grooves are located on the insulating film of the first portion of the second substrate, and grinding the first substrate at the back surface to provide a bonded wafer having a main surface exposing therein the bottom of the grooves. The grooves separate the bonded wafer into a power element forming region and a plurality of control circuit forming regions. The inverted V-grooves reduces less amount of areas for forming the control elements.

Abstract: A method of manufacturing a semiconductor layer includes preparing a first semiconductor substrate; forming an etching stop layer on the surface of the first substrate; forming an active layer on the etching stop layer; forming a crystal defect reducing layer on the active layer; preparing a second semiconductor substrate having a heat conductivity higher than the heat conductivity of the first substrate; bonding the crystal defect reducing layer to the second substrate; selectively etching the first substrate to expose the etching stop layer; selectively etching the etching stop layer to expose the active layer, whereby the active layer is disposed on the second substrate with the crystal defect reducing layer therebetween. The heat dissipation property is significantly improved by the second substrate having a high heat conductivity and by reducing the thicknesses of the active layer and the crystal defect reducing layer.

Abstract: Low temperature silicon-on-insulator wafer bonding using a silicide bond formation reaction. Dielectric isolation with silicon dioxide, diamond, silicon-nitride, and so forth yields buried resistors under trench isolated silicon islands. Buried dielectrics can be thermally susceptible films like diamond due to the low temperature of the bonding silicidation reaction. Bonding silicides also provide thermal dissipating layer between a buried diamond layer and a handle wafer for good overall thermal conductivity. Bonding silicides also act as diffusion barriers.

Abstract: A plurality of doped areas (12, 13, 14) are formed on a surface of a semiconductor wafer. A titanium nitride layer (17) is used for covering the plurality of doped areas (12, 13, 14) and for providing electrical connection between the doped areas (12, 13, 14). The titanium nitride layer (17) substantially prevents dopants from diffusing into the titanium nitride (17) and subsequently counterdoping the doped areas (12, 13, 14) during subsequent high temperature processing operations.