摘要:
A method is disclosed for fabricating a small area, self aligned guard ring in a Schottky barrier diode. A vertically-walled hole is anisotropically etched completely through a dielectric layer on a silicon substrate. A layer of doped polycrystalline silicon is deposited over the apertured dielectric layer. The polycrystalline silicon is reactively ion etched away to leave only a lining about the perimeter of the hole in the dielectric layer. The structure is heated to diffuse the dopant from the lining into the substrate. Schottky diode metal is deposited on the substrate exposed through the lined aperture in the dielectric layer.
摘要:
The present invention provides a method for planarizing a non-uniform thickness of oxide, for example silicon dioxide as is formed over oxide-filled trenches used in deep dielectric isolation in integrated circuits. The oxide is removed by a planarizing resist-etching process so that etching in thicker resist areas proceeds at a rate slower than etching in thinner resist areas. A referred etchant is HF gas and etching is preferably at an elevated temperature.
摘要:
Lateral PNP or NPN devices in isolated monocrystalline silicon pockets wherein silicon dioxide isolation surrounds the pocket and partially, below the surface, within the isolated monocrystalline region are described. The P emitter or N emitter diffusion is made over the portion of the silicon dioxide that partially extends into the monocrystalline isolated pocket. This structure reduces the vertical current injection which will give relatively high (beta) gain even at low base to emitter voltages.
摘要:
The lateral transistor is described which has both its base width and the emitter region of the transistor minimized. This minimization of the elements of the lateral transistor gives high performance. The lateral transistor which may be typically PNP transistor is formed in a monocrystalline semiconductor body having a buried N+ region within the body. A P type emitter region is located in the body. An N type base region is located around the side periphery of the emitter region. A P type collector region is located in the body surrounding the periphery of the base region. A first P+ polycrystalline silicon layer acting as an emitter contact for the emitter region is in physical and electrical contact with the emitter region and acts as its electrical contact. A second P+ polycrystalline silicon layer is located on the surface of the body to make physical and electrical contact with the collector region. A vertical insulator layer on the edge of the second polycrystalline silicon layer isolates the two polycrystalline silicon layers from one another. The N base region at its surface is located underneath the width of the vertical insulator layer. An N+ reach-through region extending from the surface of the body to the buried N+ region acts as an electrical contact through the N+ buried layer to the base region. The width of the vertical insulator has a width which is equal to the desired base width of the lateral PNP transistor plus lateral diffusions of the collector and emitter junctions of the lateral PNP. The preferred structure is to have the emitter formed around the periphery of a channel or groove which has at its base a insulating layer such as silicon dioxide. The parasitic transistor is almost totally eliminated by this buried oxide isolation.
摘要:
A high performance lateral transistor may be fabricated by first providing a monocrystalline semiconductor body having a principal surface and where the desired transistor is a PNP transistor, a buried N+ region with an N+ reach-through connecting the buried region to said principal surface. The collector region of the transistor is formed into the surface by blanket diffusing P type impurities into the desired region. An insulating layer is formed upon the top surface of the semiconductor body. An opening is made in the insulating layer where the groove or channel-emitter contact is desired. An etching of a substantially vertical walled groove into the monocrystalline semiconductor body using the patterned insulating layer as the etching mask. An N base diffusion is carried out to produce as N region around the periphery of the opening in the body. Oxygen is then ion implanted into the bottom of the groove to form a silicon dioxide region at the bottom of the groove. The P+ polycrystalline silicon layer is then formed on the surface which will in turn fill the groove with this material. The heating of the structure forms the P+ emitter region around the side edges of the P+ polycrystalline silicon filled groove. The P+ polycrystalline layer is the emitter contact, the N+ reach-through connected through the buried N+ region is the base contact and the collector contact is made to the P-type collector region.
摘要:
A method for eliminating deposited residues, for example polysilicon residue, on vertical silicon dioxide sidewalls that have been reactive ion etched includes reshaping the sidewalls to have a slope of at least +30.degree. relative to the vertical direction of the sidewall.
摘要:
A high sheet resistance structure for high density integrated circuits and the method for manufacturing such structure is given. The structure includes a silicon region separated from other silicon regions by a dielectric barrier surrounding the region. A resistor of a first conductivity, for example, N type, encompasses substantially the surface of the silicon region. Electrical contacts are made to the resistor. A region highly doped of a second conductivity, for example, P-type, is located below a portion of the resistor region. This region of second conductivity is connected to the surface. Electrical contacts are made to this varied region for biasing purposes. A second region within the same isolated silicon region may be used as a resistor. This region is located below the buried region of second conductivity. Alternatively, the described resistor regions can be connected as transistors. This allows the formation of a standard masterslice which can be personalized at a late stage in the manufacturing to either resistors or transistors in all or a portion of the standard regions.
摘要:
Excessive leakage after initial forward stress, exhibited by subsequently reverse stressed nitride defined, Schottky barrier diodes is solved by the elimination of the "mouse hole" or undercut cavity in the oxide layer beneath the nitride ring defining the Schottky contact to the underlying silicon. The aforementioned cavity is filled by depositing chemical vapor deposited (CVD) oxide onto the nitride layer, into the nitride ring and the undercut oxide cavity beneath the ring and onto the underlying silicon substrate exposed through the nitride ring. The CVD oxide is then reactively ion etched to remove it except along the vertical walls of the nitride ring and the oxide cavity. The Schottky metal is deposited on the silicon substrate exposed by the reactive ion etching step.
摘要:
A dynamic memory cell has a P+ injector region surrounded by an N+ region in an N- layer on an N+ layer. The injector region is placed between N+ source and drain regions. Holes injected into the N-layer are trapped by the high-low junctions at the N+, N- interfaces and are detected by sensing the source-drain current. Current levels are used to establish binary one and zero levels in the cell. Four masks in an aligned procedure simplify fabrication.
摘要:
A method for making a filamentary pedestal transistor is disclosed in which epitaxial silicon is formed selectively above portions of a subcollector through the use of laser radiation. A single crystal substrate, having a subcollector of higher impurity concentration, is covered by an oxide mask which is apertured at two locations above the subcollector. Polycrystalline silicon is deposited over the apertured oxide mask. The structure is exposed to laser radiation of suitable energy level and wavelength to selectively convert the polycrystalline silicon to epitaxial monocrystalline silicon within and above the oxide apertures. The transistor is completed by conventional techniques to form base, emitter and collector reach-through regions.