METHOD OF FORMING SPACERS FOR A GATE OF A TRANSISTOR
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Abstract
A method for forming spacers of a gate of a field effect transistor is provided, the gate including sides and a top and being located above a layer of a semiconductor material, the method including a step of forming a dielectric layer that covers the gate; after the step of forming the dielectric layer, at least one step of modifying the dielectric layer by ion implantation while retaining non-modified portions of the dielectric layer covering sides of the gate and being at least non-modified over their entire thickness; the ions having a hydrogen base and/or a helium base; at least one step of removing the modified dielectric layer using a selective etching of the dielectric layer, wherein the removing includes a wet etching with a base of a solution including hydrofluoric acid diluted to x % by weight, with x≦0.2, and having a pH less than or equal to 1.5.
5 Citations
32 Claims
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1-16. -16. (canceled)
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17. A method for forming spacers of a gate of a field effect transistor, the gate comprising sides and a top and being located above a layer made of a semiconductor material, the method comprising:
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a step of forming a dielectric layer that covers the gate of the transistor; after the step of forming the dielectric layer, at least one step of modifying said dielectric layer by ion implantation at least in portions of the dielectric layer that are located on a top of the gate and on either side of the gate and which are perpendicular to the sides of the gate by retaining non-modified portions of the dielectric layer coveting the sides of the gate, said non-modified portions being at least non-modified over their entire thickness the ions having a hydrogen base and/or a helium base; and at least one step of removing the modified dielectric layer using a selective etching of the modified dielectric layer relative to the layer made of a semiconductor material and relative to the non-modified dielectric layer, wherein the dielectric layer is made of a material chosen from among a silicon nitride, SiC, SiCN, and SiCBN, and wherein the selective etching of the modified dielectric layer comprises a wet etching based on a solution comprising hydrofluoric acid diluted to x % by weight, with x≦
0.2, and having a pH less than or equal to 1.5. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification