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Seh America, Inc.

Yao Huang

Karen Fleckner

H Sho Fuji

David S Lim

Jeff M Pedersen

Cynthia Buenviaje

Jeremy Hergesheimer

Wesley T Harrison

Mitchell Stephen Billington

Michael Treiber

Feng Zheng

A novel design and process for: a) a membrane electrode assembly (MEA) with aligned carbon nanotubes as a nano-scale gas distributor which yield better gas conversion efficiencies in PEM fuel cells, and (b) doped silicon flow field plates (FFP) which increase electrode conductivity of the membrane-catalyst-gas diffusion layer (GDL)-FFP interfaces of the proton exchange membrane fuel cell (PEMFC). Also, part of the invention are a stacking configuration and a gas distribution design that also enhance conductivity of carbon/metal catalyst/electrode, GDL, and FFP interfaces surfaces without crushing the FFPs. Aligned carbon nanoscale gas distributors are employed at the interfaces, thereby increasing the overall performance of the PEMFC. The FFPs are easy to manufacture and mass-producible, yet mechanically sturdy and significantly lighter in weigh than their conventional counterparts. Another novel feature of the invention is an integrated monitoring and communication/Internet system located directly or connected to the FFP.

Fuel cells incorporating nanotubes in fuel feed

A method for fabricating wafers is provided that uses a potassium-based oxidizer in the presence of hydrofluoric acid as the chemical etchant for etching the wafer edge. The potassium-based chemical etchant is preferably potassium permanganate KMnO that is mixed with hydrofluoric acid such that the ratio of hydrofluoric acid to potassium permanganate is between 2:1 and 4:1. The method for fabricating wafers initially divides a crystal ingot into a plurality of wafers before grinding the wafer edge to size and shape the wafer. The wafer can then be subjected to alkaline cleaning and acid etching. After a polysilicon layer is deposited on the wafer for gettering purposes and a silicon dioxide back seal layer, if any, is deposited, the wafer is then etched with the potassium-based chemical oxidizer in the presence of hydrofluoric acid to oxidize and remove the polysilicon layer and any silicon dioxide layer from the edge. The wafer is then rinsed and thermally annealed prior to undergoing edge polishing. In order to concentrate the potassium-based chemical etchant on the wafer edge, the opposed major surfaces can be covered, such as by being stacked in an alternating fashion with spacers. As such, the wafer edge can be reliably formed in an efficient and safe manner.

Method for etching a wafer edge using a potassium-based chemical oxidizer in the presence of hydrofluoric acid

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Vancouver, WA, United States of America

Yao Huang