Abstract: A pn-diode of SiC has a first emitter layer part doped with first dopants having a low ionization energy and a second part designed as a grid and having portions extending vertically from above and past the junction between the drift layer and the first part and being laterally separated from each other by drift layer regions for forming a pn-junction by the first part and the drift layer adjacent such portions at a vertical distance from a lower end of the grid portions. The different parameters of the device are selected to allow a depletion of the drift layer in the blocking state form a continuous depleted region between the grid portions, to thereby screen off the high electric field at the pn-junction so that it will not be exposed to high electrical fields.
Type:
Grant
Filed:
May 21, 1997
Date of Patent:
May 11, 1999
Assignee:
ABB Research Ltd.
Inventors:
Kurt Rottner, Adolf Schoner, Mietek Bakowski
Abstract: The method includes forming a gate oxide on a substrate. A stacked-amorphous-silicon (SAS) layer is then formed on the gate oxide. An anti-reflective coating (ARC) layer is formed on the SAS layer. Next, a gate structure is patterned by etching. A silicon oxynitride layer is formed on the substrate, and covered the gate structure. A BSG sidewall spacers are formed on the side walls of the gate structure. A selective epitaxial silicon is grown on the substrate by using ultra high vacuum chemical vapor deposition. Then, an ARC layer is removed to expose the top of the SAS layer. Then, a blanket ion implantation is carried out to implant p type dopant into the SAS layer, the epitaxial silicon and silicon substrate. A SALICIDE layer, a polycide layer are respectively formed on the SAS layer and the epitaxial silicon. Further, the extended source and drain are formed in the step. A thick oxide layer is formed over the substrate and gate structure for isolation. Then, contact holes are generated in the oxide layer.
Abstract: In a method of manufacturing a semiconductor device including a first MOSFET for a non-volatile memory element, a second MOSFET for an input protecting element and a third MOSFET for a logic circuit element, gate structures of the first to third MOSFETs are formed on a p-type substrate. Then, an n-type impurity is injected in the substrate in self-alignment with the gate structure for the third MOSFET with a first dose amount to form source and drain regions for the third MOSFET. An n-type impurity is simultaneously injected in the substrate in self-alignment with the gate structures for the first and second MOSFETs to form source and drain regions for the first and second MOSFETs. A side wall insulating film is formed on a side wall of each of the gate structures of the thirst to third MOSFETs. An n-type impurity is injected in parts of the source and drain regions of the third MOSFET in self-alignment with the side wall and gate structure with a second dose amount which is higher than the first dose amount.
Abstract: A gate structure in a CMOS is fabricated wherein the encapsulation material is self-aligned with the gate conductor and the gate channel. The gate conductor is formed subsequent to the device doping and heat cycles for formulation of the source and drain junction, and is preferably of greater width than the gate.
Type:
Grant
Filed:
May 23, 1996
Date of Patent:
April 27, 1999
Assignee:
International Business Machines Corporation
Abstract: A method of forming a field effect transistor includes, a) providing a silicon substrate having impurity doping of a first conductivity type; b) providing source and drain diffusion regions of a second conductivity type within the silicon substrate, the source region and the drain region being spaced from one another to define a channel region therebetween within the silicon substrate; c) providing a gate relative to the silicon substrate operatively adjacent the channel region; and d) providing respective ohmic electrical contacts to the source region and the drain region, the electrical contact to the source region comprising a substrate leaking junction, the electrical connection to the drain region not comprising a substrate leaking junction. A field effect transistor is also disclosed.
Abstract: A method of forming an insulated gate semiconductor device includes the steps of patterning an insulated gate electrode on a face of a substrate containing a first conductivity type region and forming a trench at the face using the gate electrode as a mask. Second conductivity type dopants are then deposited onto the bottom and sidewalls of the trench and diffused into the substrate to form a relatively lightly doped first body region. The gate electrode is then used again as a mask during a step of implanting a relatively high dose of second conductivity type dopants at the bottom of the trench. These implanted dopants are then partially diffused laterally and downwardly away from the bottom and sidewalls of the trench. The gate electrode is then used again to deposit first conductivity type dopants onto the sidewalls (and bottom) of the trench.
Abstract: A method of fabricating an FET includes forming an active layer including a low dopant concentration layer, forming a recess in the active layer so that the bottom of the recess is present within the low dopant concentration semiconductor layer, forming side walls in the recess, and forming a gate electrode in the-recess using the side walls as masks. The gate length can be precisely reduced by the side walls. Further, even when the active layer is anisotropically etched to form the side walls, the low dopant concentration semiconductor layer is subjected to the etching. Therefore, a part of the active layer where a greater part of channel current flows is not adversely affected by the etching. Therefore, any variation in the thickness of the active layer does not vary the channel current of the transistor.
Abstract: Short channel MOS semiconductor devices are produced by implanting impurity ions through gate electrode and gate oxide layers, before patterning the gate electrode, using a composite mask of silicon oxide and silicon nitride, to form a shallow channel region in the substrate for adjusting the threshold voltage and a deeper well region for preventing punch through. In another embodiment, impurity ions are implanted to form lightly doped and heavily doped source/drain regions in a single ion implantation step using a thermally grown oxide region having bird's beaks as a mask. Self-aligned lightly doped regions are formed under the bird's beaks.
Abstract: A dielectric layer is formed on a main surface of a semiconductor substrate. A silicon layer is formed on dielectric layer. MOS transistors are formed in silicon layer and include impurity regions in a semiconductor layer. A capacitor is formed by cooperation of the impurity region, the dielectric layer, and the semiconductor substrate. The dielectric layer also serves as an insulating film of an SOI structure. Thus, a semiconductor memory device which achieves high performance and allows high integration can easily be obtained in a DRAM having an SOI structure.
Abstract: An intentionally undoped amorphous silicon layer, a phosphorous doped amorphous silicon layer and a tungsten silicide layer are successively laminated on a gate oxide layer, and are patterned into a gate electrode of a field effect transistor; while a phosphosilicate glass layer over the gate electrode is being reflowed, the amorphous silicon layers are crystallized to a polysilicon layer, and phosphorous is less segregated at the boundary between the gate oxide layer and the polysilicon layer during the heat treatment.
Abstract: A thin-film transistor (3, 5a, 5b and 5c) is covered with a first silicon nitride film (9) formed by an LPCVD method. A first silicon oxide film (6) is formed on the first silicon nitride film (9). A silicon nitride film (7), i.e., passivation film which is formed by a plasma CVD method is provided on the first silicon oxide film (6).
Type:
Grant
Filed:
January 2, 1998
Date of Patent:
March 23, 1999
Assignees:
Mitsubishi Denki Kabushiki Kaisha, Ryoden Semiconductor System Engineering Corporation
Abstract: Dopant activation in heavily boron doped p.sup.+ --Si is achieved by applying electric current of high density. The p.sup.+ --Si was implanted by a 40 KeV BF.sup.2+ at an ion intensity 5.multidot.10.sup.15 ions per cm.sup.2 and annealed at 900.degree. C. for 30 minutes to obtain a partial boron activation according to conventional processing steps. To obtain additional activation and higher conductivity, current was gradually applied according to the invention to a current density of approximately 5.times.10.sup.6 A/cm.sup.2 was realized. The resistance of the p.sup.+ --Si gradually increases and then decreases with a precipitous drop at a threshold current. The resistance was reduced by factor of 5 to 18 times and was irreversible if an activation current threshold was reached or exceeded. The high-current-density-dopant activation occurs at room temperature.
Type:
Grant
Filed:
July 12, 1996
Date of Patent:
March 16, 1999
Assignee:
The Regents of the University of California
Abstract: A semiconductor device (20) is fabricated by doping a dielectric layer (29) located over the surface of a semiconductor substrate (21). The dielectric layer (29) contains nitrogen and is doped with silicon ions by using an ion implantation process (15) such that a peak concentration (32) of the silicon ions remains in the dielectric layer (29) during the ion implantation process (15). Doping the dielectric layer (29) reduces charge trapping in the dielectric layer (29) and reduces power slump in the semiconductor device (20) during high frequency operation.
Type:
Grant
Filed:
September 29, 1997
Date of Patent:
March 16, 1999
Assignee:
Motorola, Inc.
Inventors:
Lawrence S. Klingbeil, Jr., Mark R. Wilson
Abstract: In the production of a dual work function CMOS circuit, a polysilicon layer is produced for the purpose of forming a gate structure, the average grain diameter of which polysilicon layer is greater than the minimum extent in the gate structure, in order to suppress lateral dopant diffusion. In particular, a constriction having a width less than the average grain diameter is produced in the gate structure.
Abstract: In order to produce an integrated CMOS circuit, a dielectric layer and a silicon layer are applied to a substrate. During the formation of insulation structurers which insulate neighboring active regions in the substrate, the silicon layer is structured in such a way that it has separate sub-regions which are subsequently doped differently. By full-surface deposition of an electrically conductive layer and common structuring of the electrically conductive layer and the structured silicon layer differently doped gate electrodes and a metallization plane, by which the gate electrodes are electrically connected, are formed. Division of the silicon layer before doping prevents lateral dopant diffusion.
Abstract: To form a contact layer on source and drain electrodes of a stagger-type TFT, a conductive material is selectively sticked to the surface of the source and drain electrodes and a contact layer is selectively deposited by using the conductive material as growth species to form an active semiconductor layer on the contact layer. For an inverted-stagger-type TFT, a conductive material is selectively deposited on the surface of a contact layer to use the selectively deposited conductive material as source and drain electrodes so that patterning is unnecessary. To selectively deposit a contact layer of a TFT by alternately repeating etching and deposition, the temperature for the etching is set to 200.degree. C. or lower. A contaminated layer on the surface of a semiconductor film serving as an active semiconductor layer and contact layer of a TFT is removed by plasma at the temperature of 200.degree. C. or lower.
Abstract: A PMOS transistor is formed in a CMOS integrated circuit, having a Si.sub.1-x Ge.sub.x /Si heterojunction between the channel region and the substrate. The method is applicable to large volume CMOS IC fabrication. Germanium is implanted into a silicon substrate, through a gate oxide layer. The substrate is then annealed in a low temperature furnace, to form Si.sub.1-x Ge.sub.x in the channel region.
Abstract: The present invention is directed to a silicon carbide field effect transistor. The FET is formed on a silicon carbide monocrystalline substrate. An insulative material gate having a pair of spaced apart sidewalls is patterned on the substrate. The insulative material comprises a first insulation material overlayed by an electrically conductive layer. Within the substrate is lightly doped base regions located partially under the sidewalls of the gate and extending into the exposed substrate. Associated with the lightly doped base regions are heavily doped source regions aligned with the exposed substrate. On the underside of the substrate is a drain region to form the FET. Further in accordance with the present invention, a method to fabricate a field effect transistor is disclosed. The transistor is formed in a monocrystalline substrate of silicon carbide. Forming a transistor on the silicon carbide substrate entails depositing a first electrically insulative layer over the substrate.
Abstract: A method of making N-channel and P-channel IGFETs is disclosed. The method includes, in sequence, the steps of partially doping a first source and a first drain in a first active region of a semiconductor substrate, applying a first tube anneal while a second active region of the semiconductor substrate is devoid of source/drain doping, partially doping a second source and a second drain in the second active region, applying a second tube anneal, fully doping the first source and the first drain, applying a first rapid thermal anneal, fully doping the second source and the second drain, and applying a second rapid thermal anneal. Advantageously, the first and second tube anneals provide control over the channel junction locations, and the first and second rapid thermal anneals provide rapid drive-in for subsequent source/drain doping spaced from the channel junctions.
Type:
Grant
Filed:
September 3, 1996
Date of Patent:
March 2, 1999
Assignee:
Advanced Micro Devices, Inc.
Inventors:
Mark I. Gardner, Derick J. Wristers, H. Jim Fulford, Jr.