1. A method of manufacturing a non-volatile memory device comprising the steps of:
providing a semiconductor substrate;
forming a gate insulating film on the semiconductor substrate;
forming a floating gate on the gate insulating film, the floating gate comprising a stacked structure of an inner polysilicon layer and an outer hemispherical grain polysilicon layer;
nitrifying the hemispherical grain polysilicon layer;
forming a dielectric film by depositing (TaO)1\u2212x(TiO)xN on the nitrified hemispherical grain polysilicon layer;
inducing crystallization of the dielectric film through a thermal process using an electric furnace or a metal thermal process of the surface of the dielectric film; and
forming a conductive layer for a control gate on the dielectric film.
2. A method for manufacturing a non-volatile memory device comprising the steps of:
providing a semiconductor substrate;
forming a gate insulating film on the semiconductor substrate;
forming a floating gate on the gate insulating film;
forming a dielectric film by depositing (TaO)1\u2212x(TiO)xN on the floating gate; and
forming a conductive layer for a control gate on the dielectric film.
3. The method as claimed in claim 2, wherein the dielectric film is formed by using tantalum ethylate as a precursor.
4. The method as claimed in claim 2, wherein the floating gate is obtained by forming a conductive layer on the gate insulating film and a hemispherical grain (HSG) polysilicon layer on the conductive layer.
5. The method as claimed in claim 2, wherein the (TaO)1\u2212x(TiO)xN (0.01\u2266\xd7\u22660.09) thin film is deposited using a chemical vapor deposition method such that the mole composition ratio between Ti and Ta of the (TaO)1\u2212x(TiO)xN thin film should be 0.01-1.0:1.
6. The method as claimed in claim 2, wherein the step of forming a dielectric film by depositing (TaO)1\u2212x(TiO)xN further comprises
vaporizing a predetermined amount of a Ta(OC2H5) solution at a temperature between 140-200\xb0 C.;
vaporizing a predetermined amount of a Ti-containing solution at a temperature between 200-300\xb0 C., the Ti-containing solution comprising a solution of one or more compounds from the group consisting of TiOCH(CH3)24, TiCl4, TDMAT and TDEAT.
7. The method as claimed in claim 2, wherein the step of forming a dielectric film by depositing (TaO)1\u2212x(TiO)xN further comprises
supplying a predetermined amount of a Ta chemical vapor to the LPCVD chamber;
supplying a predetermined amount of a Ti chemical vapor to the LPCVD chamber, the predetermined amounts of the Ta chemical vapor and the Ti chemical vapor being adjusted to provide a Ti:Ta mole ratio of between 1:100 and 1:1;
supplying a predetermined amount of reaction gases NH3 and O2 to the LPCVD chamber, the predetermined amount being between 10 and 1000 sccm; and
maintaining conditions within the LPCVD chamber to generate a surface reaction between the Ta chemical vapor, the Ti chemical vapor, and the reaction gases.
8. The method as claimed in claim 2, further comprising a step of nitrifying the surface of the floating gate before forming the dielectric film.
9. The method as claimed in claim 8, wherein the step of nitrifying the floating gate further comprises one treatment step selected from a group consisting of
treating the floating gate in a plasma reactor at a temperature between 300-600\xb0 C. in an atmosphere of NH3 or N2H2 for 1-5 minutes;
treating the floating gate in a rapid thermal process unit at a temperature between 600-950\xb0 C. in an NH3 atmosphere; and
treating the floating gate in an electric furnace at a temperature between 500-1000\xb0 C. in an NH3 atmosphere.
10. The method as claimed in claim 2, further comprising the step of removing a natural oxide film from the floating gate, the step of removing the natural oxide film being completed before forming the dielectric film.
11. The method as claimed in claim 10, further comprising the step of cleaning the surface of the floating gate using a NH40H solution or a H2SO4 solution, the step of cleaning the surface of the floating gate being performed immediately before or after the step of removing a natural oxide film.
12. The method as claimed in claim 2, further comprising a thermal treatment of the dielectric layer, the thermal treatment being sufficient to induce crystallization of the dielectric film and to remove organic impurities from the dielectric film.
13. The method as claimed in claim 12, where in the thermal treatment is performed at a temperature between 650-950\xb0 C. in an atmosphere comprising at least one gas selected from a group consisting of N2O, O2 and N2.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An image processing method for converting an inputted image into an image with a relatively smaller dynamic range, the method comprising the steps of:
calculating an edge strength per position on an input image;
controlling a threshold of an epsilon filter on the basis of the calculated edge strength;
filtering the input image by the epsilon filter by use of the threshold controlled in the step of controlling the threshold; and
calculating a coefficient for converting a pixel value according to an output value in the step of filtering, and converting the pixel value per pixel by the calculated coefficient.
2. An image processing method according to claim 1, wherein
in the step of calculating the edge strength, the larger a primary differential value of a pixel value in a neighboring region of a pixel of interest is, the larger a value is calculated as the edge strength.
3. An image processing method according to claim 1, wherein
in the step of controlling the threshold, the threshold is controlled so that the larger the edge strength is, the smaller the threshold becomes.
4. An image processing method according to claim 1, wherein
in the step of controlling the threshold, the threshold is controlled so that the larger the pixel value of the input image is, the larger the threshold becomes, and the larger the edge strength is, the smaller the threshold becomes.
5. An image processing method according to claim 1, wherein
in the step of controlling the threshold, two thresholds with different values are calculated, and
in the step of filtering, a different threshold is used depending upon whether a value of a neighboring pixel is smaller or larger than a value of a pixel of interest.
6. An image processing method according to claim 5, wherein
in the step of filtering, in the case where the value of the neighboring pixel is larger than the value of the pixel of interest, the threshold with a larger value out of the two thresholds is used, and in the case where the value of the neighboring pixel is smaller than the value of the pixel of interest, the threshold with a smaller value is used.
7. An image processing method according to claim 1, further comprising the step of:
performing nonlinear transformation on a pixel level of the input image,
wherein the input image after the nonlinear transformation is filtered by the epsilon filter.
8. An image processing method according to claim 7, wherein the nonlinear transformation is logarithmic transformation.
9. An image processing apparatus for converting an inputted image into a image with a relatively smaller dynamic range, the image processing apparatus comprising:
an edge strength calculating means for calculating an edge strength per position on an input image;
an epsilon filter for filtering the input image by use of a predetermined threshold;
a threshold control means for controlling the threshold used in the epsilon filter on the basis of the edge strength calculated by the edge strength calculating means; and
a pixel value conversion means for calculating a coefficient for converting a pixel value according to an output value from the epsilon filter and converting the pixel value per pixel by the calculated coefficient.
10. An image processing apparatus according to claim 9, wherein
the edge strength calculating means is configured so that the larger a primary differential value of a pixel value in a neighboring region of a pixel of interest is, the larger a value is calculated as the edge strength.
11. An image processing apparatus according to claim 9, wherein
in the threshold control means, the threshold is controlled so that the larger the edge strength is, the smaller the threshold becomes.
12. An image processing apparatus according to claim 9, wherein
in the threshold control means, the threshold is controlled so that the larger the pixel value of the input image is, the larger the threshold becomes, and the larger the edge strength is, the smaller the threshold becomes.
13. An image processing apparatus according to claim 9, wherein
the threshold control means is configured to calculate two thresholds with different values, and use a different threshold depending upon whether a value of a neighboring pixel is smaller or larger than a pixel of interest.
14. An image processing apparatus according to claim 13, wherein
the epsilon filter is configured so that in the case where the value of the neighboring pixel is larger than the value of the pixel of interest, the threshold with a larger value out of the two thresholds is used, and in the case where the value of the neighboring pixel is smaller than the value of the pixel of interest, the threshold with a smaller value is used.
15. An image processing apparatus according to claim 9, further comprising:
a nonlinear transformation means for performing nonlinear transformation on a pixel level of the input image,
wherein the epsilon filter is configured to filter the input image after the nonlinear transformation.
16. An image processing apparatus according to claim 15, wherein
the nonlinear transformation means performs logarithmic transformation on the pixel level of the input image.