Silicon oxide-nitride-carbide thin-film with embedded nanocrystalline semiconductor particles

Patent metadata

Field	Value
Publication number	US-9222169-B2
Application number	US-46796909-A
Country	US
Kind code	B2
Filing date	May 18, 2009
Priority date	Mar 15, 2004
Publication date	Dec 29, 2015
Grant date	Dec 29, 2015

Abstract

A solar call is provided along with a method for forming a semiconductor nanocrystalline silicon insulating thin-film with a tunable bandgap. The method provides a substrate and introduces a silicon (Si) source gas with at least one of the following source gases: germanium (Ge), oxygen, nitrogen, or carbon into a high density (HD) plasma-enhanced chemical vapor deposition (PECVD) process. A SiOxNyCz thin-film embedded with a nanocrystalline semiconductor material is deposited overlying the substrate, where x, y, z≧0, and the semiconductor material is Si, Ge, or a combination of Si and Ge. As a result, a bandgap is formed in the SiOxNyCz thin-film, in the range of about 1.9 to 3.0 electron volts (eV). Typically, the semiconductor nanoparticles have a size in a range of 1 to 20 nm.

First claim

We claim:

1. A method for forming a semiconductor nanocrystalline silicon insulating thin-film with a tunable bandgap, the method comprising:
providing a substrate;
introducing a silicon (Si) source gas and at least one source gas selected from a group consisting of germanium (Ge), oxygen, nitrogen, and carbon into a high density (HD) plasma-enhanced chemical vapor deposition (PECVD) process;
depositing a SiOxNyCz thin-film embedded with a nanocrystalline semiconductor material overlying the substrate, where x, v, z≧0, and the semiconductor material is selected from a group consisting of Si, Ge, and a combination of Si and Ge;
subsequent to depositing the SiOxNyCz thin-film, annealing the SiOxNyCz thin-film; and,
modifying the size of the nanocrystalline semiconductor material in response to the annealing, forming a bandgap in the SiOxNyCz thin-film with a minimum value of 1.9 electron volts (eV) and a refractive index in a range of 1.9 to 3.5, as measured at a wavelength of 632 nanometers (nm).

2. The method of claim 1 wherein forming the bandgap in the SiOxNyCz thin film includes forming semiconductor nanoparticles having a size in a range of 1 to 20 nm.

3. The method of claim 2 wherein introducing the Si source gas into an HD PECVD process includes using an inductively coupled plasma (ICP) process as follows:
supplying power to a top electrode at a frequency in the range of 13.56 to 300 megahertz (MHz), and a power density of up to 10 watts per square centimeter (W/cm 2 );
supplying power to a bottom electrode at a frequency in the range of 50 kilohertz to 13.56 MHz, and a power density of up to 3 W/cm 2 ; and,
using an atmosphere pressure in the range of 1 to 500 mTorr.

4. The method of claim 3 wherein supplying the oxygen source gas includes supplying an oxygen source gas from a source selected from a group consisting of N 2 O, NO, O 2 , and O 3 .

5. The method of claim 3 wherein supplying the nitrogen source gas includes supplying a nitrogen source gas selected from a group consisting of N 2 and NH 3 .

6. The method of claim 3 wherein supplying the carbon source gas includes supplying a carbon source gas selected from a group consisting of alkanes (C n H 2n+2 ), alkenes (C n H 2n ), alkynes (C n H 2n−2 ), benzene (C 6 H 6 ), and toluene (C 7 H 8 ).

7. The method of claim 3 wherein supplying the Ge source gas includes supplying a Ge source gas selected from a group consisting of Ge n H 2n+2 , where n varies from 1 to 4, and GeH x R 4-x where R is selected from a group consisting of Cl, Br, and I, and where x varies from 0 to 3.

8. The method of claim 3 wherein introducing the Si source gas further includes supplying an inert gas selected from a group consisting of He, Ar, and Kr.

9. The method of claim 1 wherein forming the bandgap in the SiOxNyCz thin-film includes forming a SiOxNyCz thin-film with peak optical emission, transmission, and absorption characteristics at a wavelength in a range of 200 to 1600 nm.

10. The method of claim 1 wherein introducing the Si source gas includes supplying a source gas selected from a group consisting of SiH4, Si2H6, TEOS (tetra-ethoxy ortho-silicate), Si n H2 n+2 , where n varies from 1 to 4, and SiH x R 4-x where R is selected from a first group consisting of Cl, Br, and I, and where x varies from 0 to 3.

11. The method of claim 1 further comprising:
simultaneous with the HD PECVD process, heating the substrate to a temperature in a range of about 25 to 400° C.

12. The method of claim 1 wherein annealing the SiOxNyCz thin film includes:
heating an underlying substrate to a temperature of greater than about 400° C.;
heating for a time duration in the range of about 10 to 300 minutes; and,
heating in an atmosphere selected from a group consisting of oxygen and hydrogen, oxygen, hydrogen, and inert gases.

13. The method of claim 12 wherein the annealing includes using a process selected from a group consisting of flash annealing and laser annealing using a heat source having a radiation wavelength selected from a group consisting of about 150 to 600 nanometers (nm) and 9 to 11 micrometers.

14. The method of claim 1 further comprising:
performing a HD plasma treatment on the SiOxNyCz thin film in an H 2 atmosphere, using a substrate temperature of less than 400° C.; and,
hydrogenating the SiOxNyCz thin film.

15. The method of claim 14 wherein hydrogenating the SiOxNyCz thin film using the HD plasma process includes:
supplying power to a top electrode at a frequency in the range of 13.56 to 300 MHz, and a power density of up to 10 W/cm 2 ;
supplying power to a bottom electrode at a frequency in the range of 50 kilohertz to 13.56 MHz, and a power density of up to 3 W/cm 2 ;
using an atmosphere pressure in the range of 1 to 500 mTorr; and,
supplying an atmosphere selected from a group consisting of H 2 and an inert gas, and H 2 .

16. The method of claim 1 wherein forming the bandgap in the SiOxNyCz thin film includes forming a SiOxNyCz thin film selected from a group consisting of intrinsic and doped thin films.

17. The method of claim 16 wherein forming the doped SiOxNyCz thin film includes in-situ doping during the HD PECVD process using a source selected from a group consisting of a dopant source gas and a physical sputtering source.

18. The method of claim 1 wherein introducing the Si source gas into the HD PECVD process includes using an energy source selected from a group consisting of a microwave slot antenna, ICP, a hollow cathode, an electron cyclotron resonance (ECR) plasma source, and a cathode-coupled plasma source.

19. The method of claim 1 wherein providing the substrate includes providing a substrate from a material selected from a group consisting of plastic, glass, quartz, Si, SiC, GaN, Ge, and Si 1-x Ge x .

20. The method of claim 1 wherein providing the substrate includes forming a bottom electrode doped with a material selected from a first group consisting of n-type and p-type dopants;
wherein forming the bandgap in the SiOxNyCz thin film includes forming a SiOxNyCz thin film selected from a group consisting of a doped and intrinsic thin film; and,
the method further comprising:
forming a top electrode overlying the SiOxNyCz thin film doped with the unselected dopant from the first group.

21. The method of claim 20 wherein forming the top and bottom electrodes includes forming the top and bottom electrodes in-situ from the SiOxNyCz thin film.

22. A method for forming a semiconductor nanocrystalline silicon insulating thin-film with a tunable bandgap, the method comprising:
providing a substrate;
introducing a silicon (Si) source gas and at least one source gas selected from a group consisting of germanium (Ge), oxygen, nitrogen, and carbon into a high density (HD) plasma-enhanced chemical vapor deposition (PECVD) process;
depositing a SiOxNyCz thin-film embedded with a nanocrystalline semiconductor material overlying the substrate, where x, y, z≧0, and the semiconductor material is selected from a group consisting of Si, Ge, and a combination of Si and Ge; and,
forming a bandgap in the SiOxNyCz thin-film, with a minimum value of about 1.9 electron volts (eV) and a refractive index in a range of about 1.9 to 3.5, as measured at a wavelength of 632 nanometers (nm).

Assignees

• Joshi Pooran Chandra
• Voutsas Apostolos T
• Sharp Lab Of America Inc

Inventors

• Joshi Pooran Chandra
• Voutsas Apostolos T

Classifications

• H10P14/6922

  the material containing Si, O and at least one of H, N, C, F or other non-metal elements, e.g. SiOC, SiOC:H or SiONC · CPC title

• H10P14/6336

  in the presence of a plasma [PECVD] · CPC title

• H10P14/3461

  Nanoparticles · CPC title

• H10P14/3411

  Silicon, silicon germanium or germanium · CPC title

• H10P14/24

  using chemical vapour deposition [CVD] · CPC title