Abstract: A semiconductor memory device includes a substrate, having a plurality of cell regions, wherein the cell regions are parallel and extending along a first direction. A plurality of STI structures is disposed in the substrate, extending along the first direction to isolate the cell regions, wherein the STI structures have a uniform height lower than the substrate in the cell regions. A selection gate line is extending along a second direction and crossing over the cell regions and the STI structures. A control gate line is adjacent to the selection gate line in parallel extending along the second direction and also crosses over the cell regions and the STI structures. The selection gate line and the control gate line together form a two-transistor (2T) memory cell.

Abstract: A semiconductor structure and method of manufacture and, more particularly, a field effect transistor that has a body contact and method of manufacturing the same is provided. The structure includes a device having a raised source region of a first conductivity type and an active region below the raised source region extending to a body of the device. The active region has a second conductivity type different than the first conductivity type. A contact region is in electric contact with the active region. The method includes forming a raised source region over an active region of a device and forming a contact region of a same conductivity type as the active region, wherein the active region forms a contact body between the contact region and a body of the device.

Abstract: According to one embodiment, a method for manufacturing a semiconductor device includes forming a plurality of electrode structures above a substrate. The method includes forming an insulating film on the plurality of electrode structures to make a gap between mutually-adjacent electrode structures. The method includes forming a silicon nitride film having compressive stress above the insulating film. The method includes forming a planarization film above the silicon nitride film. The method includes planarizing a surface of the planarization film by polishing by CMP (chemical mechanical polishing) method.

Abstract: Some embodiments include methods of forming patterns. A block copolymer film may be formed over a substrate, with the block copolymer having an intrinsic glass transition temperature (Tg,O) and a degradation temperature (Td). A temperature window may be defined to correspond to temperatures (T) within the range of Tg,O?T?Td. While the block copolymer is in the upper half of the temperature window, solvent may be dispersed into the block copolymer to a process volume fraction that induces self-assembly of the block copolymer into a pattern. A defect specification may be defined, and the process volume fraction of solvent may be at level that achieves self-assembly within the defect specification. In some embodiments, the solvent may be removed from within the block copolymer while maintaining the defect specification.

Abstract: The invention discloses a vertical parasitic PNP transistor in a BiCMOS process and manufacturing method of the same, wherein an active region is isolated by STIs. The transistor includes a collector region, a base region, an emitter region, pseudo buried layers, and N-type polysilicon. The pseudo buried layers, formed at the bottom of the STIs located on both sides of the collector region, extend laterally into the active region and contact with the collector region, whose electrodes are picked up through making deep-hole contacts in the STIs. The N-type polysilicon is formed on the base region and contacts with it, whose electrodes are picked up through making metal contacts on the N-type polysilicon. The transistors can be used as output devices in high-speed and high-gain circuits, efficiently reducing the transistors area, diminishing the collector resistance, and improving the transistors performance. The method can reduce the cost without additional technological conditions.

Abstract: Bipolar junction transistors are provided in which at least one of an emitter contact, a base contact, or a collector contact thereof is formed by epitaxially growing a doped SixGe1-x layer, wherein x is 0?x?1, at a temperature of less than 500° C. The doped SixGe1-x layer comprises crystalline portions located on exposed surfaces of a crystalline semiconductor substrate and non-crystalline portions that are located on exposed surfaces of a passivation layer which can be formed and patterned on the crystalline semiconductor substrate. The doped SixGe1-x layer of the present disclosure, including the non-crystalline and crystalline portions, contains from 5 atomic percent to 40 atomic percent hydrogen.

Abstract: A thin film transistor includes a substrate; a gate electrode on the substrate; a gate insulating layer covering the gate electrode; a semiconductor layer corresponding to the gate electrode on the gate insulating layer; a protective layer covering the semiconductor layer and the gate insulating layer and having a source contact hole and a drain contact hole exposing a portion of the semiconductor layer; and a source electrode and a drain electrode on the protective layer and coupled to the semiconductor layer through the source contact hole and the drain contact hole, respectively, wherein the semiconductor layer has a source offset groove at a portion corresponding to the source contact hole of the protective layer.

Abstract: A reverse-conducting semiconductor device (RC-IGBT) including a freewheeling diode and an insulated gate bipolar transistor (IGBT), and a method for making the RC-IGBT are provided. A first layer of a first conductivity type is created on a collector side before a second layer of a second conductivity type is created on the collector side. An electrical contact in direct electrical contact with the first and second layers is created on the collector side. A shadow mask is applied on the collector side, and a third layer of the first conductivity type is created through the shadow mask. At least one electrically conductive island, which is part of a second electrical contact in the finalized RC-IGBT, is created through the shadow mask. The island is used as a mask for creating the second layer, and those parts of the third layer which are covered by the island form the second layer.

Abstract: A SiGe heterojunction bipolar transistor is fabricated by etching an epitaxially-formed structure to form a mesa that has a collector region, a cap region, and a notched SiGe base region that lies in between. A protective plug is formed in the notch of the SiGe base region so that thick non-conductive regions can be formed on the sides of the collector region and the cap region. Once the non-conductive regions have been formed, the protective plug is removed. An extrinsic base is then formed to lie in the notch and touch the base region, followed by the formation of isolation regions and an emitter region.

Abstract: A semiconductor device has a gate contact structure, including a semiconductor substrate, a polycrystalline silicon layer used as a gate electrode of a transistor, a middle conductive layer, a top metal layer having an opening exposing the polycrystalline silicon layer, and a contact plug directly contacting the polycrystalline silicon layer through the opening.

Abstract: A semiconductor device includes an inverter having an NMOSFET and a PMOSFET having sources, drains and gate electrodes respectively, the drains being connected to each other and the gate electrodes being connected to each other, and a pnp bipolar transistor including a collector (C), a base (B) and an emitter (E), the base (B) receiving an output of the inverter.

Abstract: Provided is a semiconductor device including: a silicon substrate; at least two trenches spaced apart from each other, being in parallel with each other, and being formed by vertically etching the silicon substrate from a surface thereof; an electrically insulating film for burying therein at least bottom surfaces of the trenches; a base region formed in a region of the silicon substrate located between the two trenches; and an emitter region and a collector region formed on portions of side surfaces of the trenches, respectively, the portions of the sides located above the insulating film and formed in the base region.

Abstract: A structure is disclosed including a substrate including an insulator layer on a bulk layer, and a bipolar transistor in a first region of the substrate, the bipolar transistor including at least a portion of an emitter region in the insulator layer. Another disclosed structure includes an inverted bipolar transistor in a first region of a substrate including an insulator layer on a bulk layer, the inverted bipolar transistor including an emitter region, and a back-gated transistor in a second region of the substrate, wherein a back-gate conductor of the back-gated transistor and at least a portion of the emitter region are in the same layer of material. A method of forming the structures including a bipolar transistor and back-gated transistor together is also disclosed.

Abstract: A first dielectric plug is formed in a portion of a trench that extends into a substrate of a memory device so that an upper surface of the first dielectric plug is recessed below an upper surface of the substrate. The first dielectric plug has a layer of a first dielectric material and a layer of a second dielectric material formed on the layer of the first dielectric material. A second dielectric plug of a third dielectric material is formed on the upper surface of the first dielectric plug.

Abstract: A process for manufacturing an array of bipolar transistors, wherein deep field insulation regions of dielectric material are formed in a semiconductor body, thereby defining a plurality of active areas, insulated from each other and a plurality of bipolar transistors are formed in each active area. In particular, in each active area, a first conduction region is formed at a distance from the surface of the semiconductor body; a control region is formed on the first conduction region; and, in each control region, at least two second conduction regions and at least one control contact region are formed. The control contact region is interposed between the second conduction regions and at least two surface field insulation regions are thermally grown in each active area between the control contact region and the second conduction regions.

Abstract: A power transistor. One embodiment provides a power transistor having a first terminal, a second terminal and a control terminal. A support layer is formed of a first material having a first bandgap. An active region is formed of a second material having a second bandgap wider than the first bandgap, and is disposed on the support layer. The active region is arranged to form part of a current path between the first and second terminal in a forward mode of operation. The active region includes at least one pn-junction.

Abstract: Provided is a process for forming a contact for a compound semiconductor device without electrically shorting the device. In one embodiment, a highly doped compound semiconductor material is electrically connected to a compound semiconductor material of the, same conductivity type through an opening in a compound semiconductor material of the opposite conductivity type. Another embodiment discloses a transistor including multiple compound semiconductor layers where a highly doped compound semiconductor material is electrically connected to a compound semiconductor layer of the same conductivity type through an opening in a compound semiconductor layer of the opposite conductivity type. Embodiments further include metal contacts electrically connected to the highly doped compound semiconductor material. A substantially planar semiconductor device is disclosed. In embodiments, the compound semiconductor material may be silicon carbide.

Abstract: A method and apparatus for attaching a module such as a semiconductor device, having an array of contacts arranged thereon in a given pattern to a substrate such as a printed circuit board comprises applying an array of solder blocks to the array of contacts on the module. The module is then positioned on the substrate so that the array of solder blocks contacts the array of contact pads on the substrate. Heat is then applied to reflow the solder blocks to provide mechanical and electrical connection of the module to the substrate.

Abstract: Disclosed are embodiments of a hetero-junction bipolar transistor (HBT) structure and method of forming the structure that provides substantially lower collector-to-base parasitic capacitance and collector resistance, while also lowering or maintaining base-to-emitter capacitance, emitter resistance and base resistance in order to achieve frequency capabilities in the THz range. The HBT is a collector-up HBT in which a dielectric layer and optional sidewall spacers separate the raised extrinsic base and the collector so as to reduce collector-to-base capacitance. A lower portion of the collector is single crystalline semiconductor so as to reduce collector resistance. The raised extrinsic base and the intrinsic base are stacked single crystalline epitaxial layers, where link-up is automatic and self-aligned, so as to reduce base resistance. The emitter is a heavily doped region below the top surface of a single crystalline semiconductor substrate so as to reduce emitter resistance.

Abstract: A method of fabricating a semiconductor storage cell that includes first and second source/drain regions underlying first and second trenches defined in a semiconductor substrate. Sidewalls of the trenches are lined with a charge storage stack that includes a layer of discontinuous storage elements (DSEs), which are preferably silicon nanocrystals. Spacer control gates are located in the trenches adjacent to the charge storage stacks on the trench sidewalls. The trench depth exceeds the spacer height so that a gap exists between a top of the spacers and the top of the substrate. A continuous select gate layer overlies the first trench. The gap facilitates ballistic programming of the DSEs adjacent to the gap by accelerating electrons traveling substantially perpendicular to the trench sidewalls. The storage cell may employ hot carrier injection programming to program a portion of the DSEs proximal to the source/drain regions.

Abstract: A non-volatile memory device includes a substrate having a first active region and a second active region. A first floating gate is provided over the first active region and having an edge, the first floating gate being made of a conductive material. A first spacer is connected to the edge of the first floating gate and being made of the same conductive material as that of the first floating gate. A control gate is provided proximate to the floating gate.

Abstract: Integrated circuit devices including an isolation region are provided. The devices include an integrated circuit substrate and a trench in the integrated circuit substrate that defines an active region of the integrated circuit device. A silicon layer is provided on the integrated circuit substrate that extends over an edge of the trench and along an upper portion of a first sidewall of the trench. An insulating material is positioned adjacent the silicon layer that extends across some, or all, of the trench to define the isolation region. Methods of forming such integrated circuit devices are also provided.

Abstract: A collector-up heterojunction bipolar transistor including, stacked on a substrate, an emitter layer, a base layer, and a collector layer. In this transistor the surface area of the base-emitter junction is of smaller dimensions than the surface area of the base-collector junction. Further, the material of the base layer exhibits a sensitivity of the electrical conductivity to ion implantation that is lower than the sensitivity of the electrical conductivity of the material of the emitter layer to the same ion implantation.

Abstract: Structures and methods involving at least a pair of gate oxides having different thicknesses, one suitable for use in a logic device and one suitable for use in a memory device, have been shown. The method provided by the present invention affords a technique for ultra thin dual gate oxides having different thicknesses using a low temperature process in which no etching steps are required. The method includes forming a pair of gate oxides to a first thickness, which in one embodiment, includes a thickness of less than 5 nanometers. In one embodiment, forming the pair of gate oxides includes using a low-temperature oxidation method. A thin dielectric layer is then formed on one of the pair of gate oxides which is to remain as a thin gate oxide region for a transistor for use in a logic device. The thin dielectric layer exhibits a high resistance to oxidation at high temperatures.

Abstract: In a bottom gate-type thin-film transistor manufacturing method, after ion doping, an ion stopper is removed. The ion stopper does not remain in the interlayer insulating film lying immediately above the gate electrode. The thin-film transistor has such a structure that no ion stopper, and the interlayer insulating layer is in direct contact with at least the channel region of the semiconductor layer. The impurity concentration in the vicinity of the interface between the interlayer insulating film and the semiconductor layer 4 is 1018 atoms/cc or less. This structure can prevent the back channel phenomenon and reduce variations in characteristic resulting from variations in manufacturing.

Abstract: A method of producing a hetero-junction bipolar transistor includes: laminating semiconductor layers that are to be a subcollector layer, a collector layer, a base layer, an emitter layer and an emitter cap layer successively on one surface of a semi-insulating substrate; and forming an electrode layer on the emitter cap layer. The method also includes adjusting the shape of the emitter cap layer to be a predetermined shape by wet etching; and removing end portions of the electrode layer so that the edges of the electrode layer are substantially aligned to the edges of the top face of the emitter cap layer. Furthermore, the method includes removing a surface oxidized layer formed on the emitter layer. Thus, defective etching of the emitter layer including an element P of group V is resolved, and a hetero-junction bipolar transistor having predetermined properties can be produced stably.

Abstract: A method of fabricating a high-performance, raised extrinsic base HBT having a narrow emitter width is provided. In accordance with the method, a patterned nitride pedestal region and inner spacers are employed to reduce the width of an emitter opening. The reduced width is achieved without the need of using advanced lithographic tools and/or advanced photomasks.

Abstract: Integrated circuit devices including an isolation region are provided. The devices include an integrated circuit substrate and a trench in the integrated circuit substrate that defines an active region of the integrated circuit device. A silicon layer is provided on the integrated circuit substrate that extends over an edge of the trench and along an upper portion of a first sidewall of the trench. An insulating material is positioned adjacent the silicon layer that extends across some, or all, of the trench to define the isolation region. Methods of forming such integrated circuit devices are also provided.

Abstract: An electrically erasable programmable read-only memory (EEPROM) comprises trench isolation regions whose upper surfaces are recessed compared with an upper surface of the semiconductor substrate, thereby allowing use of all surfaces of a protrusion of the semiconductor substrate between the isolation regions, including the upper surface of the semiconductor substrate, as an active region. Accordingly, the performance of a memory cell can be improved by increasing the size of an active channel region without needing to change the size of a planar unit cell.

Abstract: A new method to form flash memory devices in the manufacture of an integrated circuit device is achieved. The method comprises providing a substrate. A first film is formed comprising a first oxide layer overlying the substrate and a floating gate layer overlying the first oxide layer. A second film is formed comprising a second oxide layer overlying the first film, a control gate layer overlying the second oxide layer, and an insulating layer overlying the control gate layer. The first and second films are patterned to form stacked gates comprising floating gates and control gates. Ions are implanted into the substrate between the stacked gates to form source and drain regions. A third oxide layer is then formed on the sidewalls of the stacked gates. A plug layer is then deposited overlying the substrate and the stacked gates and filling spaces between the stacked gates.

Abstract: A process fabricates a vertical structure high carrier mobility transistor on a substrate of crystalline silicon doped with impurities of the N type, the transistor having a collector region located at a lower portion of the substrate.

Abstract: A method for forming an etching mask structure on a substrate includes etching the substrate, laterally expanding the etching mask structure, and depositing a self-aligned metal layer that is aligned to the originally masked area. The etching can be isotropic or anisotropic. The self-aligned metal layer can be distanced from the original etching masked area based on the extent of the intentionally laterally expanded etching mask layer. Following metal deposition, the initial mask structure can be removed, thus lifting off the metal atop it. The etching mask structure can be a resist and can be formed using conventional photolithography materials and techniques and can have nearly vertical sidewalls. The lateral extension can include a silylation technique of the etching mask layer following etching. The above method can be utilized to form bipolar, hetero-bipolar, or field effect transistors.

Abstract: The invention includes methods of forming field effect transistors. In one implementation, a method of forming a field effect transistor having a gate comprising a conductive metal or metal compound received over conductively doped semiconductive material includes forming transistor gate semiconductive material into a gate line over a semiconductive material channel region. The gate line includes semiconductive material sidewalls. The semiconductive material sidewalls of the gate line are oxidized. After the oxidizing, at least one of a conductive metal or metal compound is formed in electrical connection with the transistor gate semiconductive material to comprise a substantially coextensive elongated portion of a final construction of the gate line of the field effect transistor being formed.

Abstract: A method of manufacturing a semiconductor device comprising the step of epitaxially growing of an n-type doped layer of a semiconductor material using an n-type dopant gas, the growth process being performed at a pressure higher than 2.66×104 Pa.

Abstract: In a nonvolatile memory, a floating gate includes a portion of a conductive layer (150), and also includes conductive spacers (610). The spacers increase the capacitive coupling between the floating gate and the control gate (170).

Abstract: A method for making a gate in an integrated circuit. A gate layer is formed on a substrate, and a blocking layer is formed on the gate layer. The blocking layer is masked with a photoresist layer, and the photoresist layer is developed to define an exposed gate area. The blocking layer is etched in the gate area to expose the gate layer in the gate area, and the photoresist layer is removed. A metal layer is formed on the blocking layer and on the gate layer in the gate area. The metal layer is selectively reacted with the gate layer in the gate area to form a hard mask over the gate layer in the gate area. The metal layer is removed from the blocking layer. The blocking layer is selectively etched without substantially etching the hard mask in the gate area, to expose the gate layer surrounding the gate area. The exposed gate layer is etched to define a gate in the gate area. The hard mask remains on the gate, and functions as an electrical contact to the gate.

Abstract: A method for fabricating a flash memory device begins with forming in sequence a tunnel oxide layer, a floating gate, an oxide-nitride-oxide (ONO) layer, a control gate, and a hard mask nitride layer on a silicon substrate. The hard mask nitride layer, the control gate, the ONO layer, and the floating gate are then patterned in sequence. Next, a sealing nitride layer is formed on a lateral side of the patterned structure. Also, in order to form a spacer, a first insulating layer is deposited on an entire resultant structure and then selectively patterned. Thereafter, second, third and fourth insulating layers are formed in sequence on the entire resultant structure including the spacer, and a photo resist pattern is then formed on the fourth insulating layer to define a metal contact area.

Abstract: A bipolar junction transistor includes a substrate, a first layer, a second layer, and a third layer. The first layer comprises non-single-crystalline semiconductor material having a first conductivity type deposited on the substrate. The second layer comprises non-single-crystalline semiconductor material having a second conductivity type deposited on at least a portion of the first layer. The third layer comprises non-single-crystalline semiconductor material having a conductivity type different than the second conductivity type deposited on at least a portion of the second layer. The first, second, and third layers form a collector, base, and emitter of the bipolar junction transistor.

Abstract: In the case of a semiconductor device where a base electrode 11 in a collector top heterojunction bipolar transistor is disposed so as to contact with the side face of a base layer 5 in which no ion is implanted and the surface of a high resistance extrinsic emitter area 14 in which ion is implanted, the dependence of the current gain in the collector top HBT on the collector size can be diminished.

Abstract: A method of fabricating a trenched flash memory cell is provided. A plurality of shallow trench isolation structures are formed to enclose at least an active area in a silicon substrate. A doped region is formed in the silicon substrate, followed by the deposition of an isolation layer on the silicon substrate. A first photo and etching process (PEP) is performed to form two trenches within the active area. A tunnel oxide layer, a floating gate, and ONO dielectric layer are formed in the trenches, respectively. A doped polysilicon layer is then formed on the silicon substrate to fill the trenches, followed by the removal of a portion of the doped polysilicon layer to form two controlling gates in the active area. Next, a self-alignment common source is formed between the two controlling gates and a plurality of spacers are formed on either side of each controlling gate. Finally, a silicide layer is formed on the surfaces of the controlling gates and the common source.

Abstract: In an element intrinsic region 12 of a bipolar transistor, an emitter is formed by two emitter layers 31,32 so as to reduce the potential barrier presented to minority carriers, this resulting in a smooth flow of minority carriers that are injected into the base layer from the emitter, and in the element external region 13, the emitter layer 32 that acts to reduce the potential barrier to injected minority carriers is removed, thereby suppressing the injection of minority carriers from the emitter layer 31 into the base layer.

Abstract: A method for manufacturing a low voltage high frequency silicon power transistor applying epitaxial mesa structure using a minimized number of masks has a highly doped silicon n++ substrate forming the emitter. Also a low voltage high frequency silicon transistor chip presenting an epitaxial mesa technology silicon power device is presented. The silicon transistor layout presents a collector-up device with a number of single mesa collector structures. The transistor operates with its substrate as a down facing emitter, and base and collector areas together with bonding pads facing up, whereby the parasitic base-to-collector capacitance is almost entirely eliminated with the emitter as substrate. The reduced number of necessary fabrication process steps of this new structure is outlined.

Abstract: A method for embedded flash cell fabrication beyond 0.35 &Xgr;m generation. First, a relatively thick field oxide layer is formed on the P-type substrate to separate the flash cell areas and logic cell area. The flash cell areas are divided into tunnel oxide window and capacitor coupling area. Next, a conventional photolithogrpahy and etching method is used to formed a patterned photoresist on the substrate and expose flash cell areas. Then N-type conductive dopants are implanted into the substrate. For 0.35 &mgr;m generation, the concentration of dopant is increased to 5El7˜1El9 atoms/cm3. Next, the patterned photoresist layer are removed and thicker tunnel oxide and thinner gate oxide layer are formed in one processing step. Next, a doped polysilicon layer is deposited by using a conventional chemical vapor deposition over the tunnel oxide layer to serve as the floating gate of the flash cell.

Abstract: The invention relates to the manufacture of a so-called differential bipolar transistor comprising a base (1A), an emitter (2) and a collector (3), the base (1A) being formed by applying a doped semiconducting layer (1) which locally borders on a monocrystalline part (3) of the semiconductor body (10) where it forms the (monocrystalline) base (1A), and which semiconducting layer (1) borders, outside said monocrystalline part, on a non-monocrystalline part (4, 8) of the semiconductor body (10) where it forms a (non-monocrystalline) connecting region (1B) of the base (1A). The non-monocrystalline part (4, 8) of the semiconductor body (10) is obtained by covering the semiconductor body (10) with a mask (20) and replacing on either side thereof a part (8) of the semiconductor body (10) by an electrically insulating region (8) and by providing this, prior to the application of the semiconducting layer (1) with a polycrystalline semiconducting layer (4).

Abstract: A method for forming upon a microelectronics layer upon a substrate employed within a microelectronics fabrication a silicon oxide dielectric layer with enhanced density and reduced mobile species, ionic concentration and ionic mobility. There is provided a substrate employed within a microelectronics fabrication. There is formed upon the substrate a blanket undoped silicon oxide glass dielectric layer employing ozone assisted near atmospheric pressure thermal chemical vapor deposition (APCVD) from tetra-ethyl-ortho-silicate (TEOS) vapor, wherein a high flow rate ratio of ozone gas to TEOS vapor affords enhanced density and reduced mobile species, ionic concentration and ionic mobility in the blanket silicon oxide glass dielectric layer. There is then formed a blanket boron-phosphorus doped silicon containing glass dielectric layer over the substrate employing ozone assisted near atmospheric pressure thermal chemical vapor deposition (APCVD) to complete the dielectric layer.

Abstract: In a method manufacturing a semiconductor device, a semiconductor layer having a device forming region is formed on substrate. Next, a region except for the device forming region is changed into an insulator. In this case, a conducting path is left across the semiconductor device to electrically connect the semiconductor device with an adjacent semiconductor device. Subsequently, the device forming region is etched on the condition that the conducting path is left. Finally, the conducting path is disrupted after the etching process. Thus, the semiconductor device and the adjacent semiconductor device are left in an electrical contact via the conducting path during the etching process. Consequently, the uniformity of the etching between the semiconductor devices is largely improved.

Abstract: A method of fabricating an HBT using differential epitaxy. By using an emitter mask and an exside-inside spacer structure, a self-aligned fabrication of an emitter contact and a base contact is carried out. The emitter contact layer is made from amorphous silicon. Since the entire process sequence is very temperature-stable and can be carried out at lower implantation energies than conventional methods, HBT's having a high layer quality can be fabricated by the method of the invention which is suitable for mass production and with which high oscillation frequencies can be accomplished.

Abstract: A process and structure for an improved collector-up bipolar transistor. The base is formed after the emitter is implanted to eliminate base damage during oxygen implantation typical in prior art collector-up bipolar transistors. In a preferred embodiment, an emitter layer of GaAlAs is implanted with oxygen in the extrinsic emitter region to damage the material and make it insulative. The base is epitaxially grown at low temperature to insure the emitter material remains damaged and insulative.