Method of making a field emitter device using randomly located nuclei as an etch mask
AssigneeMicroelectronics and Computer Technology Corporation
InventorNalin Kumar
Life of this patent
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Abstract
Method of making a field emitter device with submicron low work function emission tips without using photolithography. The method includes depositing in situ by evaporating or sputtering a discontinuous etch mask comprising randomly located discrete nuclei. In one embodiment an ion etch is applied to a low work function material covered by a discontinuous mask to form valleys in the low work function material with pyramid shaped emission tips therebetween. In another embodiment an ion etch is applied to an electrically conductive base material covered by a discontinuous mask to form valleys in the base material with pyramid shaped base tips therebetween. The base material is then coated with a low work function material to form emission tips thereon.
Claims58
A method of making a field emitter device, comprising the following steps:
- providing a substrate;
- depositing a continuous layer of a low work function material on the substrate;
- depositing in situ by evaporation or sputtering a non-polymerized randomly patterned etch mask with a relatively high melting point on the low work function material, said etch mask comprising randomly located discrete nuclei with discontinuities therebetween thereby exposing portions of the low work function material beneath the discontinuities while covering other portions thereof beneath the nuclei;
- etching the exposed portions of the low work function material by applying an ion etch after the deposition of nuclei begins, wherein the low work function material etches at a greater rate than the etch mask so as to form valleys in the low work function material with emission tips between the valleys;
- and
- removing the etch mask from the low work function material.
A method of making a field emitter device, comprising the following steps:
- providing a substrate;
- depositing a continuous layer of a low work function material on the substrate;
- depositing in situ by evaporation or sputtering a non-polymerized randomly patterned etch mask with a relatively high melting point on the base material, said etch mask comprising randomly located discrete nuclei with discontinuities therebetween thereby exposing portions of the base material beneath the discontinuities while covering other portions thereof beneath the nuclei;
- etching the exposed portions of the base material by applying an ion etch after the deposition of nuclei begins, wherein the base material etches at a greater rate than the etch mask so as to form valleys in the base material with base tips between the valleys;
- removing the etch mask from the base material;
- and then
- depositing a low work function material on the base material, thereby forming emission tips between the valleys.
A method of making a field emitter device, comprising the following steps in the sequence set forth:
- providing a substrate with a planar top surface;
- depositing a continuous layer of a low work function material on the substrate wherein the work function of the low work function material is less than 2.5 electron-volts;
- depositing in situ a discontinuous layer of a randomly patterned etch mask on the low work function material by evaporation or sputtering, said etch mask consisting of randomly located discrete nuclei selected from the group consisting of aluminum-oxide, carbon and gold wherein discontinuities between the nuclei are formed as the nuclei are deposited on the low work function material thereby exposing portions of the low work function material beneath the discontinuities while covering other portions thereof beneath the nuclei;
- etching the exposed portions of the low work function material by applying an ion etch after depositing the mask, wherein the low work function material etches at at least twice the rate of the etch mask until the etch mask is completely removed so as to form vertical valleys in the low work function material with rectangular pyramid shaped emission tips between the valleys;
- and
- etching the entire surface of the low work function material by continuing to apply the ion etch until the emission tips assume a conical pyramid shape.
A method of making a field emitter device, comprising the following steps in the sequence set forth:
- providing a substrate with a planar top surface;
- depositing a continuous layer of an electrically conductive base material on the substrate
- depositing in situ a discontinuous layer of a randomly patterned etch mask on the base material by evaporation or sputtering, said etch mask consisting of randomly located discrete nuclei selected from the group consisting of aluminum-oxide, carbon and gold wherein discontinuities between the nuclei are formed as the nuclei are deposited on the base material thereby exposing portions of the base material beneath the discontinuities while covering other portions thereof beneath the nuclei;
- etching the exposed portions of the low work function material by applying an ion etch after depositing the mask, wherein the base material etches at at least twice the rate of the etch mask until the etch mask is completely removed so as to form vertical valleys in the base material with rectangular base tips between the valleys;
- etching the entire surface of the base material by continuing to apply the ion etch until the base tips assume a conical pyramid shape;
- and
- depositing a low work function material on the base material, wherein the work function of the low work function material is less than 2.5 electron-volts, thereby forming emission tips between the valleys which assume a conical pyramid shape.
Dependencies are inferred from the claim text.