Fengyan Y Zhang

US Patent:

6350699, Feb 26, 2002

Filed:

May 30, 2000

Appl. No.:

09/584407

Inventors:

Jer-shen Maa - Vancouver WA
Fengyan Zhang - Vancouver WA

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H01L 2100

US Classification:

438720, 216 67, 216 75, 438742

Abstract:

A method of anisotropically etching metals, especially iridium, platinum, ruthenium, osmium, and rhenium using a non-chlorofluorocarbon, fluorine-based chemistry. A substrate having metal deposited thereon, is inserted into an ECR plasma etch chamber and heated. A fluorine containing gas, such as, carbon tetrafluoride (CF ), nitrogen trifluoride (NF ) or sulfur hexafluoride (SF ) is introduced into the chamber and ionized to form a plasma. Fluorine ions within the plasma strike, or contact, the metal to form volatile metal-fluorine compounds. The metal-fluorine compounds are exhausted away from the substrate to reduce, or eliminate, redeposition of etch reactants.

US Patent:

6372034, Apr 16, 2002

Filed:

Oct 12, 2000

Appl. No.:

09/687827

Inventors:

Wei-Wei Zhuang - Vancouver WA
Jer-shen Maa - Vancouver WA
Fengyan Zhang - Vancouver WA
Sheng Teng Hsu - Camas WA

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H01L 2122

US Classification:

10628719, 438 3

Abstract:

A method of preparing a PGO solution for spin coating includes preparing a 2-methoxyethanol organic solvent; adding Pb(OCH CO). 3H O to the organic solvent at ambient temperature and pressure in a nitrogen-filled glaved box to form Pb in methoxyethanol; refluxing the solution in a nitrogen atmosphere at 150Â C. for at least two hours; fractionally distilling the refluxed solution at approximately 150Â C. to remove all of the water from the solution; cooling the solution to room temperature; determining the Pb concentration of the solution; adding the 2-methoxyethanol solution to the Pb 2-methoxyethanol until a desired Pb concentration is achieved; combining Ge(OR) , where R is taken the group of Rs consisting of CH CH and CH(CH ) , and 2-methoxyethanol; and adding Ge(OR) 2-methoxyethanol to PbO 2-methoxyethanol to form the PGO solution having a predetermined metal ion concentration and a predetermined Pb:Ge molar ration.

US Patent:

6399521, Jun 4, 2002

Filed:

May 21, 1999

Appl. No.:

09/316646

Inventors:

Fengyan Zhang - Vancouver WA
Sheng Teng Hsu - Camas WA

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H01L 2131

US Classification:

438785, 438 3, 438650, 438643

Abstract:

An IrâMâO composite film has been provided that is useful in forming an electrode of a ferroelectric capacitor, where M includes a variety of refractory metals. The Ir combination film effectively prevents oxygen diffusion, and is resistant to high temperature annealing in oxygen environments. When used with an underlying barrier layer made from oxidizing the same variety of M transition metals, the resulting conductive barrier also suppresses the diffusion of Ir into any underlying Si substrates. As a result, Ir silicide products are not formed, which degrade the electrode interface characteristics. The Ir combination film remains conductive, not peeling or forming hillocks, during high temperature annealing processes, even in oxygen. The IrâMâO conductive electrode/barrier structures are useful in nonvolatile MFMIS (metal/ferro/metal/insulator/silicon) memory devices, DRAMs, capacitors, pyroelectric infrared sensors, optical displays, and piezoelectric transducers. A method for forming an IrâMâO composite film barrier layer with an oxidized refractory metal barrier layer is also provided.

US Patent:

6410343, Jun 25, 2002

Filed:

Apr 28, 1999

Appl. No.:

09/301420

Inventors:

Tingkai Li - Vancouver WA
Fengyan Zhang - Vancouver WA
Yoshi Ono - Camas WA
Sheng Teng Hsu - Camas WA

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H01L 2100

US Classification:

438 3, 438239, 438933

Abstract:

A ferroelectric Pb Ge O (PGO) thin film is provided with a metal organic vapor deposition (MOCVD) process and RTP (Rapid Thermal Process) annealing techniques. The PGO film is substantially crystallization with c-axis orientation at temperature between 450 and 650Â C. The PGO film has an average grain size of about 0. 5 microns, with a deviation in grain size uniformity of less than 10%. Good ferroelectric properties are obtained for a 150 nm thick film with Ir electrodes. The films also show fatigue-free characteristics: no fatigue was observed up to 1Ã10 switching cycles. The leakage currents increase with increasing applied voltage, and are about 3. 6Ã10 A/cm at 100 kV/cm. The dielectric constant shows a behavior similar to most ferroelectric materials, with a maximum dielectric constant of about 45. These high quality MOCVD Pb Ge O films can be used for high density single transistor ferroelectric memory applications because of the homogeneity of the PGO film grain size.

US Patent:

6410346, Jun 25, 2002

Filed:

Dec 6, 2001

Appl. No.:

10/010186

Inventors:

Tingkai Li - Vancouver WA
Fengyan Zhang - Vancouver WA
Yoshi Ono - Camas WA
Sheng Teng Hsu - Camas WA

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H01L 2100

US Classification:

438 3, 438680, 257295, 257306, 257310

Abstract:

A Pb GeO phase PGO thin film is provided. This film has ferroelastic properties that make it ideal for many microelectromechanical applications or as decoupling capacitors in high speed multichip modules. This PGO film is uniquely formed in a MOCVD process that permits a thin film, less than 1 mm, of material to be deposited. The process mixes Pd and germanium in a solvent. The solution is heated to form a precursor vapor which is decomposed. The method provides deposition temperatures and pressures. The as-deposited film is also annealed to enhanced the films ferroelastic characteristics. A ferroelastic capacitor made from the present invention PGO film is also provided.

US Patent:

6420740, Jul 16, 2002

Filed:

May 24, 1999

Appl. No.:

09/317780

Inventors:

Fengyan Zhang - Vancouver WA
Tingkai Li - Vancouver WA
Sheng Teng Hsu - Camas WA

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H01L 2976

US Classification:

257295, 257296, 257306, 257310

Abstract:

The ferroelectric structure including a Pt/Ir layered electrode used in conjunction with a lead germanate (Pb Ge O ) thin film is provided. The electrode exhibits good adhesion to the substrate, and barrier properties resistant to oxygen and lead. Ferroelectric properties are improved, without detriment to the leakage current, by using a thin IrO layer formed in situ, during the MOCVD lead germanate (Pb Ge O ) thin film process. By using a Pt/Ir electrode, a relatively low MOCVD processing temperature is required to achieve c-axis oriented lead germanate (Pb Ge O ) thin film. The temperature range of MOCVD caxis oriented lead germanate (Pb Ge O ) thin film on top of Pt/Ir is 400-500Â C. Further, a relatively large nucleation density is obtained, as compared to using single-layer iridium electrode. Therefore, the lead germanate (Pb Ge O ) thin film has a smooth surface, a homogeneous microstructure, and homogeneous ferroelectric properties. A method of forming the above-mentioned multi-layered electrode ferroelectric structure is also provided.

US Patent:

6440752, Aug 27, 2002

Filed:

Mar 26, 2001

Appl. No.:

09/817712

Inventors:

Fengyan Zhang - Vancouver WA
Tingkai Li - Vancouver WA
Hong Ying - San Jose CA
Yoshi Ono - Camas WA
Sheng Teng Hsu - Camas WA

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H01G 706

US Classification:

438 3, 438240

Abstract:

An electrode for use in a ferroelectric device includes a bottom electrode; a ferroelectric layer; and a top electrode formed on the ferroelectric layer and formed of a combination of metals, including a first metal take from the group of metals consisting of platinum and iridium, and a second metal taken from the group of metals consisting of aluminum and titanium; wherein the top electrode acts as a passivation layer and wherein the top electrode remains conductive following high temperature annealing in a hydrogen atmosphere. A method of forming a hydrogen-resistant electrode in a ferroelectric device includes forming a bottom electrode; forming a ferroelectric layer on the bottom electrode; depositing a top electrode on the ferroelectric layer; including depositing, simultaneously, a first metal taken from the group of metals consisting of platinum and iridium; and a second metal taken from the group of metals consisting of aluminum and titanium; and forming a passivation layer by annealing the structure in an oxygen atmosphere to form an oxide passivation layer on the top electrode.

US Patent:

6441417, Aug 27, 2002

Filed:

Mar 28, 2001

Appl. No.:

09/820022

Inventors:

Fengyan Zhang - Vancouver WA
Yanjun Ma - Vancouver WA
Jer-Shen Maa - Vancouver WA
Wei-Wei Zhuang - Vancouver WA
Sheng Teng Hsu - Camas WA

Assignee:

Sharp Laboratories of America, Inc. - Camas WA

International Classification:

H01L 2972

US Classification:

257295, 257410, 257412

Abstract:

A thin film structure includes a substantially single-phase, c-axis PGO film on an insulator for use in metal ferroelectric insulator semiconductor single transistor non-volatile memory applications. The PGO on insulator structure can also be used in capacitors, pyroelectric infrared sensors, optical displays, optical switches, piezoelectric transducers, and surface acoustic wave devices. In a preferred embodiment, the PGO film is deposited on a Zirconium Oxide insulator layer.