Method to produce a field-emitter array with controlled apex sharpness

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This patent describes a method for producing field-emitter arrays (FEAs) in which the sharpness of the emitter tips (apexes) is precisely controlled and made uniform. The process uses crystal orientation-dependent etching and repeated cycles of oxidation and removal of an oxide layer on a single-crystal semiconductor mold to shape the holes. These specially shaped molds are then coated with electron-emitting material and processed so the field-emitter tips have a controlled and tunable apex radius, leading to uniform electron emission characteristics across the array.

Use CasesContent extracted from patent full text and abstract with AI.

• High-resolution electron sources for electron microscopy and lithography.
• Electron guns for flat panel displays or vacuum microelectronics.
• Field-emission cathodes in X-ray tubes.
• High-brightness electron sources for free-electron lasers.
• Advanced imaging systems requiring uniform electron beams.
• Research instrumentation that utilizes precise field emission arrays.

BenefitsContent extracted from patent full text and abstract with AI.

• The method achieves highly uniform and controlled sharpness of the field-emitter apexes, improving device performance and yield.
• Minimizes undesirable side emissions and parasitic effects, leading to higher quality and more reliable devices.
• Enables customization of emitter tip sharpness (apex radius between 1 and 100 nm) for different application requirements.
• Facilitates mass production of high-quality FEAs with consistent characteristics across large arrays.
• Improves longevity and current-carrying capacity of field emitters by optimizing apex curvature.
• Reduces variation in electron emission, enhancing the resolution and brightness of electron sources.

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Patent Abstract

A method of uniformly controlling the apex sharpness of field-emitter arrays fabricated by a molding technique are described. The method utilizes the repeated oxidation and etching of the mold substrate (101,102,104,105) consisting of single-crystal semiconductor mold wafers, where the mold holes (110,111,112,113) for individual emitters are fabricated by utilizing the crystal orientation dependence of the etching rate.