Abstract: In the fabrication of an integrated circuit, a shallow trench for isolation of a vertical bipolar transistor comprised in the circuit is fabricated by providing a semiconductor substrate of a first doping type. A buried collector region of a second doping type for the bipolar transistor is formed in the substrate. A silicon layer is epitaxially grown on top of the substrate. An active region of the second doping type for the bipolar transistor is formed in the epitaxially grown silicon layer, the active region being located above the buried collector region. A first trench is formed in the epitaxially grown silicon layer and the silicon substrate, the first trench surrounding, in a horizontal plane, the active region and extending vertically a distance into the substrate. An electrically insulating material is formed in the first trench.

Abstract: A method in the fabrication of a monolithically integrated vertical device on an SOI substrate comprises the steps of providing an SOI substrate including, from bottom to top, a silicon bulk material, an insulating layer, and an monocrystalline silicon layer; forming an opening in the substrate, which extends into the bulk-material, forming silicon oxide on exposed silicon surfaces in the opening and subsequently removing the formed oxide, whereby steps in the opening are formed; forming a region of epitaxial silicon in the opening; and forming a deep trench in an area around the opening, whereby the steps in the opening are removed.

Abstract: A method for producing vertical bipolar transistors having different voltage breakdown and high-frequency performance characteristics on a single die comprises forming, for each of the vertical bipolar transistors, a buried collector region, and base and emitter regions above the buried collector region. The lateral extensions and locations of the base and emitter regions and of the buried collector region are, for each of the vertical bipolar transistors, selected to create an overlap between the base and emitter regions, and the buried collector region, as seen from above, wherein at least some of the overlaps are selected to be different.

Abstract: A method in the fabrication of an I2L circuit comprises (i) forming a common base of a lateral bipolar transistor and emitter of a vertical bipolar multicollector transistor, a common collector of the lateral transistor and base of the vertical multicollector transistor, and an emitter of the lateral transistor in a substrate; (ii) forming, from a first deposited polycrystalline layer, a contact region for the common collector/base and a contact region for the emitter of the lateral transistor; (iii) forming an isolation structure for electric isolation of the polycrystalline contact region for the common collector/base; and (iv) forming, from a second deposited polycrystalline layer, a contact region for the common base/emitter and multiple collectors of the vertical multicollector transistor.

Abstract: A method in the fabrication of an integrated bipolar circuit comprises the steps of: providing a p-type substrate; forming in the substrate a buried n+-type region and an n-type region above the buried n+-type region; forming field isolation areas around the n-type region; forming a PMOS gate region on the n-type region; forming a diffused n+-type contact from the upper surface of the substrate to the buried n+-type region; the contact being separated from the n-type region; forming a p-type polysilicon source on the n-type region; forming a p-type source in the n-type region; forming a p-type drain in the n-type region; and connecting the PMOS transistor structure to operate as a PNP transistor, wherein the source is connected to the gate and constitutes an emitter of the PNP transistor; the drain constitutes a collector of the PNP transistor; and the n-type region constitutes a base of the PNP transistor.

Abstract: A method in the fabrication of a monolithically integrated vertical device on an SOI substrate comprises the steps of providing an SOI substrate including, from bottom to top, a silicon bulk material, an insulating layer, and an monocrystalline silicon layer; forming an opening in the substrate, which extends into the bulk-material, forming silicon oxide on exposed silicon surfaces in the opening and subsequently removing the formed oxide, whereby steps in the opening are formed; forming a region of epitaxial silicon in the opening; and forming a deep trench in an area around the opening, whereby the steps in the opening are removed.

Abstract: A monolithically integrated circuit comprises a thin film resistor (8) with low resistance and low temperature coefficient; a high frequency lateral power transistor device (9) including gate (17), source (16) and drain (15) regions, and a Faraday shield layer region (22; 22?) above the gate region; and at least a first metallization layer (28) there above for electrical connection of the gate (17), source (16) and drain (15) regions through via holes filled with conductive material (29c–d). The thin film resistor (8) and the Faraday shield layer region (22; 22?) are made in the same conductive layer, which is arranged below the first metallization layer (28).

Abstract: A method in the fabrication of an I2L circuit comprises (i) forming a common base of a lateral bipolar transistor and emitter of a vertical bipolar multicollector transistor, a common collector of the lateral transistor and base of the vertical multicollector transistor, and an emitter of the lateral transistor in a substrate; (ii) forming, from a first deposited polycrystalline layer, a contact region for the common collector/base and a contact region for the emitter of the lateral transistor; (iii) forming an isolation structure for electric isolation of the polycrystalline contact region for the common collector/base; and (iv) forming, from a second deposited polycrystalline layer, a contact region for the common base/emitter and multiple collectors of the vertical multicollector transistor.

Abstract: A method for producing vertical bipolar transistors having different voltage breakdown and high-frequency performance characteristics on a single die comprises forming, for each of the vertical bipolar transistors, a buried collector region, and base and emitter regions above the buried collector region. The lateral extensions and locations of the base and emitter regions and of the buried collector region are, for each of the vertical bipolar transistors, selected to create an overlap between the base and emitter regions, and the buried collector region, as seen from above, wherein at least some of the overlaps are selected to be different.

Abstract: A method in the fabrication of an integrated bipolar circuit for forming a p/n-junction varactor is disclosed. The method featuring the steps of providing a p-doped substrate (10; 10, 41); forming a buried n+-doped region (31) in the substrate; forming in the substrate an n-doped region (41) above the buried n+-doped region (31); forming field isolation (81) around the n-doped region (41); multiple ion implanting the n-doped region (41); forming a p+-doped region (151) on the n-doped region (41); forming an n+-doped contact region to the buried n+-doped region (31), the contact region being separated from the n-doped region (41); and heat treating the hereby obtained structure to set the doping profiles of the doped regions. The multiple ion implantation of the n-doped region (41); the formation of the p+-doped region (151); and the heat treatment are performed to obtain a hyper-abrupt p+/n-junction within the n-doped region (41).

Abstract: A method to provide a triple well in an epitaxially based CMOS or B:CMOS process comprises the step of implanting the triple well prior to the epitaxial deposition.

Abstract: A method in the fabrication of a silicon-germanium mesa transistor in a semiconductor process flow comprises the steps of providing a p-type doped silicon bulk substrate (10) having an n+-type doped surface region (31) being a subcollector; depositing epitaxially thereon a silicon layer (41) comprising n-type dopant; depositing epitaxially thereon a silicon layer (174) comprising germanium and p-type dopant; forming in the epitaxial layers (41, 174) field isolation areas (81) around, in a horizontal plane, a portion of the epitaxial layers (41, 174) to simultaneously define an n-type doped collector region (41) on the subcollector (31); a p-type doped base region (174) thereon; and an n-type doped collector plug on the subcollector (31), but separated from the n-type doped collector region (41) and the p-type doped base region (174); and forming in the p-type doped base region (174) an n-type doped emitter region.

Abstract: In a bipolar double-poly transistor comprising a layer of base silicon (1?) on a silicon substrate (2?), a first layer of silicon dioxide (3?) on the base silicon layer (1?), an emitter window (4?) extending through the first layer (3?) of silicon dioxide and the base silicon layer (1?), a second layer (5?) of silicon dioxide in the emitter window (4?), silicon nitride spacers (6?) on the second layer (5?) of silicon dioxide in the emitter window (4?), and emitter silicon (9?) in the emitter window (4?), an isolating silicon nitride seal is provided to separate the base silicon (1?) from the emitter silicon (9?) to prevent short-circuiting between the base silicon (1?) and the emitter silicon (9?) in the transistor.

Abstract: A method for selective etching in the manufacture of a semiconductor device comprises: forming a layer (6) of silicon-germanium on a substrate (1) of monocrystalline silicon or on a substrate at least comprising a surface layer of monocrystalline silicon, depositing at least a dielectric layer (7) on the silicon-germanium layer (6) and patterning the resultant structure (8), whereafter the dielectric layer (7) and the silicon-germanium layer (6) are etched away within a predetermined region (9). Preferably, the silicon-germanium layer (6) is amorphous, whereby the dielectric layer (7) is deposited on the amorphous silicon-germanium layer (6) in such a manner to prevent crystallization of the amorphous layer. After etching the structure may be heat-treated such that the amorphous layer crystallizes. The method is preferably applicable for etching an emitter window in the manufacture of a bipolar transistor having a self-registered base-emitter structure.

Abstract: A method for forming an electrical device structure in an integrated circuit comprises providing a substrate; forming a passivation layer thereon; forming a plurality of through holes in the passivation layer, the through holes; removing substrate material under the passivation layer by means of isotropic etching, thus forming at least a first cavity in the substrate beneath the plurality of through holes; forming a dielectric layer on top of the passivation layer to plug the through holes, thereby creating a membrane; and creating an electrical device, such as e.g. an inductor, above the membrane.

Abstract: In an integrated circuit, particularly an integrated circuit for radio frequency applications, a semiconductor structure for isolation of semiconductor devices that includes a semiconductor substrate, at least one shallow trench extending vertically into the substrate, a deep trench laterally located within the shallow trench, where the deep trench extends vertically further into the substrate. The deep trench is self aligned to the shallow trench with a controlled lateral distance between an edge of the shallow trench and an edge of the deep trench and the lateral extensions of the shallow and deep trenches, respectively, are independently chosen.

Abstract: In order to produce an electrical connection to an inner layer such as a bottom diffusion (103), which has a good electrical conductivity and is located inside a bipolar semiconductor device isolated by trenches (119) and which for example forms a subcollector of a NPN-transistor, a hole (157) in a trench is used. The hole is filled with electrically conducting material and extends from the surface of the device to the bottom diffusion (103), so that the electrically conducting material in the hole is in contact therewith. The hole (157) is made aligned with a sidewall of the trench (119) by using selective etching. The hole can be made at the same time as contact holes for metallization are made and then also be filled in the metallization step, to contact the bottom diffusion. For a lateral PNP-transistor the hole can be made as a closed groove constituting the outer confinement of the base area, passing all around the transistor.

Abstract: A bipolar transistor of type NPN has an active region at the surface of the component, which is surrounded, as seen along the surface of the component, in the conventional way by thick field oxide areas. The active region is partly covered by an electrically isolating surface layer, preferably comprising a nitride layer. A base region in the active region is defined by a well-defined opening, which is lithographically produced, in the electrically isolating surface layer. For a bipolar lateral transistor of type PNP, which instead has emitter and collector regions surrounded by such thick field oxide areas, the emitter and collector regions can in the corresponding way be defined by a lithographically defined opening in an electrically isolating surface layer. Owing to the well defined openings the base-collector capacitance and the emitter-collector capacitance respectively can be reduced in these cases, what results in better high frequency characteristics of the transistors.

Abstract: In the fabrication of a transistor device, particularly a low-voltage high-frequency transistor for use in mobile telecommunications, a method for improving the transistor performance and the high-frequency characteristics of the device is described. The method includes providing a semiconductor substrate (1) with an n-doped collector layer (5) surrounded by isolation areas (4), implanting antimony ions into the collector layer such that a thin highly n-doped layer (18) is formed in the uppermost portion of the collector layer, and forming a base on top of said thin highly n-doped layer (18).

Abstract: Apparatus and methods for manufacturing low-resistant substrate contacts in integrated circuits are disclosed. The contacts are low resistive conducting plugs and are located outside the areas of active components. The substrate is connected from the top portion in order to obtain a low resistance. Multiple metal plugs electrically interconnect the substrate of the integrated circuit with the top portion of the integrated circuit.