Browse Prior Art Database

Field-Emission Triode Integrated-Circuit Construction Method

IP.com Disclosure Number: IPCOM000036729D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 77K

Publishing Venue

IBM

Related People

Cronin, JE: AUTHOR [+3]

Abstract

Microelectronic device-processing steps are selectively combined to make integrated circuits comprised of field-emission triodes for the active devices instead of semiconductor devices. Sharp, field-emission tips are formed which are self-aligned to a control grid by this process.

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Field-Emission Triode Integrated-Circuit Construction Method

Microelectronic device-processing steps are selectively combined to make integrated circuits comprised of field-emission triodes for the active devices instead of semiconductor devices. Sharp, field-emission tips are formed which are self-aligned to a control grid by this process.

Referring to Fig. 1, insulating substrate 12 is coated with a conductor 14 and patterned, if required. Boron-phosphorous-silicon glass (BPSG) 16 and spun-on glass 18 are applied and reflowed to form a smooth surface. An image comprised of an array of circles is then photo-processed and etched through layers 18 and 16, stopping on conductor 14. A conformal layer of parylene is then deposited, followed by anisotropic etching to leave sidewall coatings 20. Dilute hydrofluoric acid is used to etch away the more porous glass 18 without seriously attacking denser glass 16 and not attacking parylene sidewall coatings 20 at all.

Referring to Fig. 2, tungsten 22 is deposited and planarized. Then, parylene 20 is etched back, and sputter etching is used to shape tungsten 22 to a sharp tip in emitter regions 22E while edges are beveled in control grid regions 22G. Parylene (not shown) is added and planarized to provide a flat surface and protection of emitter tips during the next etching process. Tungsten 22G is patterned and etched to create control grid lines (shown parallel to the plane of the figure) which are slightly wider than emit...