Intel Corporation

Daniel N Tang

Gregory E Atwood

Krishna Kumar Parat

Glen N Wada

Wen-Juei Lu

Simon Y Wang

Himanshu Choksi

Simon M Tam

Stefan K Lai

Tong-Chern Ong

Baylor B Triplett

Susan L Kao

The encapsulation of gate stacks of a semiconductor device in an oxide insulative layer and in a silicon nitride etch-stop layer allows the formation of a contact filling for connection to underlying diffusion regions without risk of accidental diffusion contact to gate shorts created by the contact filling. As a result, the gate stacks may be patterned closer together, thus reducing the cell size and increasing the cell density. Furthermore, use of the etch-stop layer makes contact lithography easier since the size of the contact opening can be increased and contact alignment tolerance made less stringent without concern of increasing the cell size or of creating diffusion contact to gate shorts.

Self-aligned contact process in semiconductor fabrication and device therefrom

Self-aligned contact process in semiconductor fabrication

A method of forming a memory device with improved isolation between diffusion lines. Parallel, spaced apart thick oxide strips are grown on a substrate. Next, spaced apart, parallel strips having a polysilicon and nitride layer, oriented perpendicular to the first strips, are formed. The oxide between the second strips is removed, followed by an implantation to form source and drain regions. The nitride layer on the second strips is removed on those strips between two drain diffusions and an oxidation is performed to form self-aligned thick oxide over the source and drain regions. The strips from which the nitride has been removed are also oxidized, thus providing isolation between adjacent drain lines. In the formation of floating gate memory devices, a second polysilicon layer is deposited, and patterned in one direction to form strips overlying the second strips. After deposition of an intergate dielectric and a third polysilicon layer, a further patterning step is performed to form strips perpendicular to the second strips and second polysilicon layer and an etch is performed to etch the third polysilicon layer, intergate dielectric, second polysilicon layer and first polysilicon layer not covered by the patterning layer.

Isolation between diffusion lines in a memory array

A method of reducing the degradation effects associated with avalanche injection or tunnelling of hot-electrons in a field-effect semiconductor device is disclosed. The method of the present invention includes covering the active regions of the semiconductor device with a protective titanium barrier layer which is deposited directly underneath the ordinary metalization layers used for connecting the devices to bit and word lines within an array. Inclusion of the titanium barrier layer in a flash memory device results in a substantial improvement in the erasetime push-out and reduces excess charge loss normally associated with hot-electron devices.

Method of reducing hot-electron degradation in semiconductor devices

A method of forming a doped region within a monocrystalline silicon layer of an integrated circuit having an electrically erasable and electrically programmable memory device on a semiconductor substrate, wherein the doped region lies within a channel region near a drain region, but does not lie within a source region. After a patterned layer is formed over the channel region, the substrate is doped by ion implantation with a first dopant at a tilt angle no less than a minimum tilt angle and at about a predetermined azimuthal angle, such that a significant number of ions enter a drain region and a channel region near the drain region and substantially no ions enter a source region. The first dopant is the same dopant type as the monocrystalline silicon layer dopant. The drain region is masked. The source region is doped with a second dopant. The second dopant is an opposite dopant type as the monocrystalline silicon layer dopant. The source region and the drain region are doped with a third dopant. The third dopant is the same dopant type as the second dopant. The third dopant dose is heavier than the first dopant dose, and the second dopant diffusion coefficient is greater than the third dopant diffusion coefficient.

Method of making electrically erasable and electrically programmable

A method and apparatus for self-aligning a source region with a field oxide region and a polysilicon gate and word line in a semiconductor device. This method and apparatus allows reduced memory cell size and improved device density by substantially eliminating the bird's beak encroachment and corner rounding effects usually found between neighboring cells due to inadequacies in the prior art photolithography process. This method and apparatus is particularly appropriate for use with EPROM, Flash EPROM, EEPROM, or other types of memory cells and in periphery devices.

Process for self aligning a source region with a field oxide region and

A method and apparatus for self-aligning a source region with a field oxide region and a polysilicon gate and word line in a semiconductor device. This method and apparatus allows reduced memory cell size and improved device density by substantially eliminating the bird's beak encroachment and corner rounding effects usually found between neighboring cells due to inadequacies in the prior art photolighography process.

Self-aligned source process and apparatus

A method for growing a high quality oxide layer on the surface of a polysilicon film for use as an interpoly dielectric. The method comprises depositing a silicon film on a wafer and implanting the silicon film with phosphorous ions. The wafers are then sent into a diffusion tube to activate the dopant. This operation is carried out in an ambient of dry oxygen and the result is the silicon film is now polysilicon and an oxide layer has been grown on the polysilicon film. The wafers are then implanted using argon ions, the implantation is carried out through the oxide layer. The result is the surface layers of the polysilicon layer are rendered amorphous. The oxide layer grown on the polysilicon film is then removed. A new oxide layer is then grown on the polysilicon film. The result is an oxide layer with excellent physical and electrical characteristics.

High quality oxide on an ion implanted polysilicon surface

A method for growing tunnel oxides on a specially treated substrate surface. The method comprises steps for roughening the substrate surface to induce low tunneling voltage in the subsequently grown tunnel oxide layer. The tunnel oxide layer is grown in a low temperature steam cycle to further provide enhanced tunneling. The surface treatment comprises the steps of growing a first oxide layer to seal the surface of the substrate followed by growing a second oxide on the first oxide layer. In the preferred embodiment, a plasma etch utilizing an oxide etcher with high energy ion bombardment and an aluminum electrode is utilized to etch through the first and second oxide layers. The aluminum electrode causes sputtered aluminum on the second oxide layer's surface. The sputtered aluminum blocks the anisotropic etching leaving a grass type oxide residue on the substrate surface. The etching continues, overetching into the substrate surface. The grass type oxide residue causes pitting to occur on the substrate surface. This pitting, resulting in sharpened features on the surface, yields enhanced tunneling characteristics for a subsequently grown tunnel oxide layer. The residue is then removed and the surface cleaned. The tunnel oxide layer is grown in a low temperture steam cycle to preserve and enhance the sharp tips for the purpose of enhanced tunneling.

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San Jose, CA, United States of America

Daniel N Tang