Boron etch-stop layer and methods related thereto
View Patent ↗A method for forming an etch-stop layer and a resulting structure fabricated therefrom. The etch-stop layer has a semiconductor layer having a first surface and a boron layer formed below the first surface of the semiconductor layer. The boron layer has a full-width half-maximum (FWHM) thickness value of less than 100 nanometers. The boron layer is formed by a chemical vapor deposition (CVD) system.
1. A method to form an electronic device, the method comprising:
flowing a boron precursor gas over a substrate in a chemical vapor deposition chamber, the boron precursor gas forming a boron layer thereby acting as an etch-stop layer, the etch-stop layer being formed below a first surface of the substrate, the etch-stop layer being less than 100 nanometers in thickness when measured as a full-width half-maximum (FWIHM) value;
forming one or more spacers on a surface of the substrate to provide a self-aligning structure;
doping the one or more spacers with carbon atoms; and
injecting carbon atoms remotely from the one or more spacers by annealing the substrate thereby allowing the carbon atoms to diffuse into the etch-stop layer.
2. The method of claim 1 wherein the boron layer is less than about 20 nanometers in thickness when measured as a FWHM value.
3. The method of claim 1 wherein the anneal step is performed at 1000° C. for about 10 seconds.
4. The method of claim 1 further comprising:
flowing a carbon precursor gas over the substrate in the deposition chamber; and
flowing a germanium precursor gas over the substrate in the deposition chamber so as to limit a diffusivity value of boron atoms within the boron layer.
5. The method of claim 1 wherein the boron precursor gas is diborane flowing at between five standard cubic centimeters per minute (sccm) and 1000 sccm.
6. The method of claim 1 wherein the boron precursor gas is boron trichloride flowing at between five standard cubic centimeters per minute (sccm) and 1000 sccm.
7. The method of claim 1 further comprising flowing a silicon precursor gas over the substrate in the deposition chamber.
8. An etch-stop layer comprising:
a semiconductor substrate having a first surface;
a boron layer formed below the first surface of the semiconductor substrate and having a full-width half-maximum (FWHM) thickness value of less than 100 nanometers, the boron layer being formed by a chemical vapor deposition (CVD) system;
a germanium profile comprised of germanium atoms formed substantially within the boron layer and having a germanium fraction of less than one percent to about 20 percent; and
a carbon profile comprised of carbon atoms formed substantially within the boron layer and having a concentration within the profile area of between 10 18 and 10 21 atoms per cubic centimeter.
9. The etch-stop layer of claim 8 wherein the boron layer is less than about 20 nanometers in thickness when measured as a FWHM value.
10. The etch-stop layer of claim 8 wherein the semiconductor substrate is a silicon substrate.
11. The etch-stop layer of claim 8 wherein the semiconductor substrate is an epitaxial silicon film.
12. The etch-stop layer of claim 8 wherein the semiconductor substrate is a deposited silicon film.
13. The etch-stop layer of claim 8 wherein the semiconductor substrate is a silicon-germanium substrate.
14. The etch-stop layer of claim 8 wherein the semiconductor substrate is an epitaxial silicon-germanium film.
15. The etch-stop layer of claim 8 wherein the semiconductor substrate is a silicon-carbide substrate.
16. The etch-stop layer of claim 8 wherein the semiconductor substrate is an epitaxial silicon-carbide film.
17. The etch-stop layer of claim 8 wherein the boron layer is less than about 20 nanometers in thickness when measured as a FWHM value.