Semiconductor devices, CMOS image sensors, and methods of manufacturing same

Abstract

A semiconductor device includes: a trench device isolating region formed in a substrate to define a photodiode active region; a channel stop impurity region formed in the substrate contacting the device isolating region, wherein the channel stop impurity region surrounds a bottom and a sidewall of the device isolating region; and a photodiode formed within the photodiode active region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an equivalent circuit diagram of a unit pixel of a CMOS image sensor according to an exemplary embodiment of the present invention.

FIG. 2 is a plan view partially illustrating a pixel array unit, according to an exemplary embodiment of the present invention, for embodying the CMOS image sensor illustrated in FIG. 1.

FIGS. 3A through 3F are sectional views illustrating a method of manufacturing the CMOS image sensor according to an exemplary embodiment of the present invention, taken along a line I-I of FIG. 2.

FIG. 4 is a diagrammatic view illustrating a computer processor system provided with the CMOS image sensor according to an exemplary embodiment of the present invention.

FIG. 5 is a graph showing a boron density in relation to the sidewall depth of the specimens resulting from Experiments 3 and 4 and Comparison 2.

FIG. 6 is a photograph showing a trench device isolating region by Experiment 2.

Claims

1. A method of manufacturing a semiconductor device comprising: forming a trench in a substrate to define a photodiode active region;doping an impurity into a bottom and a sidewall of the trench to form a channel stop impurity region, wherein the channel stop impurity region surrounds the bottom and the sidewall of the trench;forming a trench device isolating region by forming a gap-filling material layer into the impurity-doped trench; andforming a photodiode in the photodiode active region.

2. The method of claim 1, wherein the doping step is performed using plasma doping.

3. The method of claim 2, further comprising forming an oxide layer within the trench before the doping step.

4. The method of claim 3, wherein the plasma doping is performed at an energy in a range of about 1 kV to about 7 kV.

5. The method of claim 2, wherein the plasma doping is performed by a dose in a range of about 1.0E13 atoms/cm2 to about 1.0E18 atoms/cm2.

6. The method of claim 2, wherein the plasma doping is performed using at least one of a dopant gas or a dilution gas.

7. The method of claim 6, wherein the dopant gas comprises at least one material selected from the group consisting of BF3, B2H6, and BCl3.

8. The method of claim 6, wherein the dilution gas comprises at least one material selected from the group consisting of H2, N2, O2, F2, He, Ar, and Xe.

9. The method of claim 1, wherein the trench is comprised of a deep trench configuration.

10. The method of claim 9, wherein the depth of the trench is about 1 to 4 μm.

11. The method of claim 1, wherein the substrate comprises a base substrate and an epitaxial layer formed on the base substrate, and wherein the trench is formed to penetrate through the epitaxial layer.

12. The method of claim 1, wherein forming the photodiode comprises: forming a lower impurity region within the photodiode active region; andforming an upper impurity region on the lower impurity region using plasma doping.

13. The method of claim 1, wherein the semiconductor device comprises an image sensor.

14. A method of manufacturing an image sensor comprising: forming a circuit trench within a peripheral circuit region of a substrate to define a circuit active region, and forming a pixel trench within the pixel region of the substrate to define a photodiode active region;doping an impurity into a bottom and a sidewall of the pixel trench to form a channel stop impurity region, wherein the channel stop impurity region surrounds the bottom and the sidewall of the pixel trench;forming a gap-filling material layer into the circuit trench to form a circuit trench device isolating region;forming a gap-filling material layer into the impurity-doped pixel trench to form a pixel trench device isolating region; andforming a photodiode within the photodiode active region.

15. The method of claim 14, wherein the depth of the pixel trench is greater than the depth of the circuit trench.

16. The method of claim 15, wherein the depth of the pixel trench is about 1 μm to about 4 μm.

17. The method of claim 14, wherein the doping step is performed using plasma doping.

18. The method of claim 17, further comprising forming an oxide layer within the pixel trench before the doping step.

19. The method of claim 17, wherein the plasma doping is performed using at least one of a dopant gas or a dilution gas.

20. The method of claim 14, wherein the substrate comprises a base substrate and an epitaxial layer formed on the base substrate, wherein the circuit trench is formed within the epitaxial layer, and wherein the pixel trench is formed to penetrate through the epitaxial layer.

21. The method of claim 14, wherein forming the photodiode comprises: forming a lower impurity region within the photodiode active region; andforming an upper impurity region on the lower impurity region using plasma doping.

22. A method of manufacturing an image sensor comprising: forming a trench within a substrate to define a photodiode active region;doping an impurity into a bottom and a sidewall of the trench;forming a gap-filling material layer into the impurity-doped trench to form a trench device isolating region; andforming a photodiode in the photodiode active region.

23. The method of claim 21, further comprising forming an oxide layer within the pixel trench before the doping step.

24. The method of claim 22, wherein the doping step comprises plasma doping using at least one of a dopant gas or a dilution gas.

25. The method of claim 22, wherein the trench is comprised of a deep trench configuration.

26. The method of claim 22, wherein the substrate comprises a base substrate and an epitaxial layer formed on the base substrate, and wherein the trench is formed to penetrate through the epitaxial layer.

27. The method of claim 22, wherein the forming of the photodiode comprises: forming a lower impurity region within the photodiode active region; andforming an upper impurity region on the lower impurity region using plasma doping.

28. A semiconductor device comprising: a trench device isolating region formed in a substrate to define a photodiode active region;a channel stop impurity region formed in the substrate contacting the device isolating region, wherein the channel stop impurity region surrounds a bottom and a sidewall of the device isolating region; anda photodiode formed within the photodiode active region.

29. The semiconductor device of claim 28, wherein an impurity density within the channel stop impurity region is continuously decreased away from the device isolating region.

30. The semiconductor device of claim 28, wherein a thickness of the channel stop impurity region on the side of the device isolating region has a ratio of 0.5 to 1 with respect to a thickness of the channel stop impurity region under the device isolating region.

31. The semiconductor device of claim 28, wherein the trench is comprised of a deep trench configuration.

32. The semiconductor device of claim 31, wherein the depth of the trench is about 1 μm to about 4 μm.

33. The semiconductor device of claim 28, wherein the substrate comprises a base substrate and an epitaxial layer formed on the base substrate, and wherein the trench penetrates through the epitaxial layer.

34. The semiconductor device of claim 28, wherein the semiconductor device comprises an image sensor.

35. An image sensor comprising: a substrate having a pixel region and a peripheral circuit region;a circuit trench device isolating region formed in the peripheral circuit region to define a circuit active region;a pixel trench device isolating region formed in the pixel region to define a photodiode active region;a channel stop impurity region formed in the substrate contacting the pixel trench device isolating region, wherein the channel stop impurity region surrounds a bottom and a sidewall of the pixel trench device isolating region; anda photodiode formed in the photodiode active region.

36. The image sensor of claim 35, wherein the depth of the pixel trench device isolating region is greater than the depth of the circuit trench device isolating region.

37. The image sensor of claim 36, wherein the depth of the pixel trench device isolating region is about 1 μm to about 4 μm.

38. The image sensor of claim 35, wherein an impurity density within the channel stop impurity region is continuously decreased away from the pixel trench device isolating region.

39. The image sensor of claim 35, wherein a thickness of the channel stop impurity region on the side of the pixel trench device isolating region has a ratio of 0.5 to 1 with respect to a thickness of the channel stop impurity region under the device isolating region.

40. The image sensor of claim 35, wherein the substrate comprises a base substrate and an epitaxial layer stacked on the base substrate, wherein the pixel trench device isolating region is formed within the epitaxial layer, and wherein the pixel trench device isolating region penetrates through the epitaxial layer.