International Business Machines Corporation

Henry J Geipel, Jr

Larry Alan Nesbit

Paul E Bakeman, Jr

Peter Edwin Cottrell

John Michael Wursthorn

Andres G Fortino

Charles W Koburger, Iii

Pai-Hung Pan

Francis Roger White

Lawrence G Heller

Ronald R Troutman

Ronald R Silverman

Robert M Quinn

Ning Hsieh

Jeffrey P Kasold

Donald McAlpine Kenney

Charles A Schaefer

Richard B Shasteen

An oxygen-impervious pad structure which reduces the bird's beak profiles in semi-recessed oxide isolation regions. The sidewalls of a conventional silicon oxide - silicon nitride pad are coated with a thick layer of oxynitride. A thin layer of oxynitride is grown on the substrate surface prior to deposition of the thick oxynitride layer. The thick oxynitride layer prevents lateral oxidizing specie diffusion through the oxide layer of the conventional pad, and the thin oxynitride layer prevents lateral oxidizing specie diffusion through the pad-substrate interface into the substrate region beneath the pad.

Growth of bird's beak free semi-rox

A contact structure suitable for use in a CMOS device to prevent or suppress the latch-up phenomenon in the device. It uses two degeneratively doped regions of different conductivity type with a tunnel injecting interface therebetween and a conductive segment contiguous to one of the two regions. Using such a structure as the source of an FET in a CMOS arrangement causes the emitter area and the base spreading resistance of the corresponding parasitic bipolar transistor to be reduced. This in turn causes the current gain of the parasitic transistor to decrease and the latch-up phenomenon to be prevented or suppressed.

CMOS contacting structure having degeneratively doped regions for the

A process is provided for fabricating a semiconductor structure wherein the structure has to be exposed to certain oxidizing conditions during certain of its processing steps, such as its high temperature annealing in an oxidizing ambient. It includes depositing a 'sacrificial' layer, such as silicon, to provide a uniformly oxidizing surface during subsequent annealing operations. This sacrificial layer, which oxidizes uniformly, produces an oxide layer which also etches uniformly. Thus, after the annealing is completed, the surface oxide is removed through etching and the sacrificial layer is then also removed through a different etching step.

Process for fabricating semiconductor devices utilizing a protective

A very simple process is provided, with reduced processing time, for making a CMOS structure using a single polysilicon, or other refractory metal, layer which includes forming a thin gate oxide on both N and P type semiconductor layers of a common substrate, forming a gate electrode simultaneously on the N type and on the P type layers and selectively implanting an N type impurity to form N+ source and drain regions in the P type layer. The semiconductor layers are then oxidized to form substantially thicker oxide, such a silicon dioxide, adjacent to the sides of the gate electrode over the P type layer than the thickness of the oxide adjacent to the sides of the gate electrode over the N type layer. Without using a mask, a P type impurity is implanted into the N type layer to form P+ source and drain regions.

Simple process for making complementary transistors

A simple process is provided for making a planar CMOS structure wherein isolation regions required by bulk CMOS structures are first formed, an N channel device field region is self-aligned to an N well region in a semiconductor substrate and a refractory material is twice defined for forming P and N channels, the first definition masking P channel source and drain regions while defining the N channel and the second definition defining the P channel while using a photoresist layer to mask the N channel. In the process, a technique which uses a single mask level defines the well region and self-aligns the necessary field doping to the well region to provide closely spaced N and P channel devices.

Process for making complementary transistors by sequential implantations

A simple process is provided which forms a bulk CMOS structure by depositing a layer of material which resists oxidation, e.g., a barrier layer of silicon nitride on an N- semiconductor substrate, forming a P well in the substrate through a given segment of the barrier layer, removing a first segment of the barrier layer to form N+ regions for N channel source and drain and N- substrate contact, removing a second segment of the barrier layer to form a P+ field region, removing a third segment of the barrier layer to form P+ regions for source and drain of a P channel device, forming a first control electrode having a given work function for the P channel device which acts as an ion barrier and then forming a second control electrode between the N channel source and drain regions having a work function different from that of the first control electrode.

Method of making high density complementary transistors

An improved method of fabricating a silicide structure includes depositing a metal, e.g., molybdenum or tungsten, directly onto a thin insulating layer of silicon dioxide and/or silicon nitride formed on a semiconductor substrate, co-depositing the metal and silicon onto the metal layer and then depositing silicon onto the co-deposited metal-silicon layer. This structure is annealed at a temperature sufficient to form a metal silicide between the thin insulating layer and the layer of silicon. The silicon layer serves as a source of silicon for the metal layer which is consumed during the annealing step to form, along with the co-deposited metal-silicon layer, a relatively thick metal silicide layer directly on the thin silicon dioxide layer. A sufficiently thick silicon layer is initially provided on the co-deposited metal-silicon layer so that a portion of the initial silicon layer remains after the annealing step has been completed. This excess silicon may be oxidized to form a passivating layer on top of the thick metal silicide layer. If all or a part of the silicon in the remaining silicon layer after annealing is removed, the thick metal silicide layer may be exposed to an oxidizing ambient for self-passivation. In this latter instance, the pure metal precipitates in the silicide resulting in a line with even greater conductivity than a pure silicide line, which is very desirable for interconnections.

Method of fabricating a highly conductive structure

A method of providing self-passivating interconnection electrodes for semiconductor devices which provides low resistivity composite polysiliconsilicide electrodes. In the method the formation of oxidation induced voids in polysilicon underlying the silicide is eliminated by deposition of polysilicon and stoichiometric proportions of silicon and a silicide-forming metal. These steps are followed by deposition of a silicon layer having a thickness determined to provide between 30 and 100 percent of the silicon required to form a silicon dioxide passivation layer. Subsequent thermal oxidation of the layered electrode structure provides a self-passivated structure useful for fabrication of silicon gate MOSFET devices as well as other integrated circuit structures.

Fabrication method for high conductivity, void-free polysilicon-silicide

A method of providing less than one micron p-n junction regions for IGFET devices in which a high concentration of arsenic is implanted so that its peak lies near the surface of a semiconductor substrate. Phosphorus is also implanted with an energy to provide a maximum concentration below that of the arsenic and of a magnitude at least one order of magnitude less than that of arsenic. An oxidation/anneal step thermally diffuses the implanted ions to form a junction less than one micron in thickness.

Method for forming IGFET devices having improved drain voltage

A method for forming shallow low leakage ion implanted source/drain regions in an integrated circuit environment including semirecessed oxide isolation regions in which high parasitic device threshold voltages are provided by an oxidizing/annealing post implant process. Arsenic ions are implanted into a recessed oxide isolated substrate followed by a wet oxidation process and a non-oxidizing annealing process for a period of time to provide a passivating dielectric over low leakage source/drain regions of less than one micron junction depth and to provide adequate high temperature annealing to reduce the charge effects in the oxide isolation regions caused by the implanted arsenic ions.

Method of making low leakage shallow junction IGFET devices

A method of making a transistor array includes forming a plurality of gate electrodes insulated from a semiconductor substrate having an impurity of a given conductivity, introducing a first impurity having a conductivity opposite to that of the given conductivity into a given region of the substrate which is adjacent to an edge of each of the gate electrodes, introducing a second impurity having the given conductivity into given regions adjacent to selected gate electrodes, the second impurity having a significantly higher diffusivity than that of the first impurity in the semiconductor substrate, and driving the second impurity along the surface of the semiconductor substrate to form in the substrate under each of the selected gate electrodes a region having a concentration of impurity of the given conductivity higher than that of the semiconductor substrate. The transistor array may be used, e.g. to make a read only memory (ROM) by connecting appropriate current sensing means to each of the given regions to indicate the presence or absence of the higher diffusivity impurity when a predetermined voltage is applied to the gate electrodes. In one embodiment, the semiconductor substrate is made of P type conductivity, the first impurity is arsenic which produces N type conductivity regions and the second impurity is boron, which produces P type conductivity. Since boron has a higher diffusivity than arsenic, after they are driven by heating the boron impurity produces a high threshold region under the gate electrode when introduced in sufficiently high concentration.

Growing community of inventors

Essex Junction, VT, United States of America

Henry J Geipel, Jr