Vertical device with sidewall spacer, methods of forming sidewall spacers and field effect transistors, and patterning method
View Patent ↗A growth material that grows selectively on the vertical sidewalls of a vertical device forms sidewall spacers on substantially vertical sidewalls of the vertical device that is disposed on a horizontal substrate surface of a semiconductor substrate. A spacer-like seed liner may be provided on the vertical sidewalls of the vertical device to control selective growth. The vertical device may be a gate electrode of a field effect transistor (FET). With selectively grown sidewall spacers, heavily doped contact regions of the FET may be precisely spaced apart from the gate electrode. The distance of the heavily doped contact regions to the gate electrode does not depend from the height of the gate electrode. Distances of more than 150 nm between the heavily doped contact region and the gate electrode may be achieved so as to facilitate the formation of, for example, DMOS devices.
1. A method of manufacturing an integrated circuit, the method comprising:
providing a semiconductor substrate, wherein the semiconductor substrate comprises a first section including a first material, wherein the first material adjoins a horizontal substrate surface of the semiconductor substrate;
providing a first structure on the horizontal substrate surface of the semiconductor substrate, the first structure including at least one vertical sidewall adjoining the first section of the substrate surface, wherein the first structure comprises a second section that includes a second material, at least part of the first section is not covered by the first structure, and the second material is exposed at the at least one vertical sidewall; and
providing a sidewall spacer, wherein the sidewall spacer is elongated along the at least one vertical sidewall of the first structure and is formed of a third material resulting from a gaseous precursor, the first and second materials and the gaseous precursor being selected such that the third material is selectively grown on the second material;
wherein the providing of the first structure comprises:
providing an inner section of the first structure on the semiconductor substrate, the first structure including at least one vertical sidewall; and
providing a seed liner on the at least one vertical sidewall of the inner section, wherein the seed liner forms the second section.
2. The method of claim 1 , wherein providing the seed liner comprises:
depositing a conformal liner of the second material in a thickness of 5 to 40 nm; and
anisotropically etching the conformal liner of the second material, wherein residual portions of the conformal liner of the second material form the seed liner.
3. The method of claim 2 , wherein depositing the conformal liner comprises supplying SiH 4 in an environment containing H 2 at a temperature of about 500° C. to about 650° C. and a pressure of about 600 mTorr.
4. The method of claim 1 , wherein the second material includes one of amorphous silicon and polycrystalline silicon, the gaseous precursor consists of tetraethylene orthosilane, and the tetraethylene orthosilane is supplied in an environment containing ozone at a temperature between 300° C. and 500° C. such that silicon oxide grows selectively on the second section.
5. The method of claim 1 , wherein the second material includes one of amorphous silicon and polycrystalline silicon, the gaseous precursor consists of SiH 2 Cl 2 , and a mixture of SiH 2 Cl 2 , HCl and H 2 is supplied at a temperature of about 850° C. to about 1050° C. and a flow rate ratio of HCl to SiH 2 Cl 2 of at least 2:1 such that polysilicon grows selectively on the second section.
6. The method of claim 1 , wherein the second material includes one of amorphous silicon and polycrystalline silicon, the gaseous precursor consists of WF 6 , and WF 6 and SiH 4 are supplied at a temperature of about 280° C. to about 350° C., a total gas pressure of 100 mTorr and a flow rate ratio of SiH 4 to WF 6 of 0.6 or less such that tungsten grows selectively on the second section.
7. The method of claim 1 , wherein the integrated circuit comprises a field effect transistor, the field effect transistor being at least partially defined by portions of the semiconductor substrate and comprising a dielectric liner defined by at least a portion of the first section and a gate electrode formed on at least a portion of the dielectric liner and providing the at least one vertical sidewall of the first structure such that the second material is provided on at least one portion of the gate electrode, and the third material forming the sidewall spacer is selectively grown over the at least one portion of the gate electrode including the second material.
8. The method of claim 1 , further comprising:
providing a secondary structure adjacent the sidewall spacer such that the secondary structure is aligned with the first structure.
9. The method of claim 8 , wherein the secondary structure includes a further structure that is formed by deposition of a deposition material on the substrate surface and the sidewall spacer.
10. The method of claim 8 , wherein the secondary structure includes a doped region within the semiconductor substrate, the doped region being formed by implantation of a doping material into an implant section of the semiconductor substrate, and the sidewall spacer serves as an implant mask.
11. The method of claim 8 , wherein the secondary structure includes a buried secondary device being formed by etching a trench into the semiconductor substrate, and the sidewall spacer provides an etch mask for etching the trench.
12. The method of claim 1 , wherein the sidewall spacer has a uniform thickness along a length of the sidewall spacer.