1. 결정질 실리콘 태양전지의 기술과제 울산대학교 공과대학 첨단소재공학부 교수 천 희 곤
Education & Training Center
For Photovoltaic and Wind Power Engineering

2. 태양전지 종류 및 제조 방법

3. Single Crystalline Solar Cell
Front
Rear

4. Multi Crystalline Solar Cell
Front
Rear

5. Silicon Solar Cell 구조

6. Single Crystalline Solar Cell

7. 태양광 System

8. Photovoltaic Value Chain

9. PV 기술 적용 사례

10. Single Crystalline Solar Cell

11. Single Crystalline Solar Cell

12. Single Crystalline Solar Cell

13. 태양광 가격 분포

14. Low-Cost Si Materials for PV

15. 태양전지용 Silicon 원소재 계통도

16. Wafer Production

17. Surface Texturing

18. Cell Process

19. Basic Steps of Solar Cell

20. 상용 Si 태양전지 개념도

21. Si 태양전지 효율 최고 기록

22. Buried Contact Solar Cell

23. Back Contact Solar Cell
Front
Rear

24. Back Contact Solar Cell

25. Sunpower IBC Solar Cell

26. Emitter Wrap Through Cell

27. Laser Fired Contacts Cell

28. Laser Firing Cell for mc-Si PV

29. 효율 향상 방안

30. Substrates for Higher Stabilized Efficiency

31. Law of the Minimum

32. For Low Cost High Efficiency Si Solar Cell

33. Rear Surface

34. Advanced Manufacturing Technology

35. Metallization Pastes

36. Common Cell Design

37. Newer Cell Design

38. Newer Cell – Complex

39. Thick Film Patterning Technology Summary

40. Inkjet Printing

41. Inkjet Printing

42. Back Surface Reflector 구조
Overview : 실리콘 태양전지 고도화 표면
passivation
반사방지막
Texturing
Emitter
Doping
Junction
isolation
Contact
Firing
저저항 전극
미세화
Back Surface Reflector 구조
기판 Bowing 방지
Thin Wafer < 200 μm
Bulk Surface Field 형성
Bulk
& gettering
저저항 전극의 미세 패턴 형성
전극/실리콘의 접촉저항 저감
Selective emitter 구조의 최적화 (cost-effective) 前面
後面/Bulk
후면 반사구조 (BSR)
후면 passivation 및 local contact 구조 최적화
기판품위 향상 (Ga doped p-type, n-type Si)

43. 기술 개발 방향

44. 기술 개발 방향

45. 기술 개발 방향

46. 기술 개발 방향

48. 기술 개발 방향

49. Introduction PERL Cell OECO Cell 24.5% at sc-Si wafer
23% at mc-Si wafer

50. Introduction Recent Process Improved Process mc-Si wafer
damage removal and
texture etching in bath
uniform n+ diffusion
(dj : 0.3~0.5 micron)
PECVD p-SiN anti-reflection coating
Electrode by screen print
(rear Al, front Ag paste)
Co-firing
Edge isolation by laser
Module
RIE Etching
Selective Emitter formation
Local Back Surface Field
Double passivation layer
Double screen printing
Back Contact Structure

51. Tecture etching with RIE Process
Typical pyramid structure
with Chemical Etching
Inverted pyramid structure
with Reactive Ion Etching
Changes of surface statement according to time of process
1min
2min
15min

52. Tecture etching with RIE Process
acidic texture with
isotropic ecth
alkaline texture with
anisotropic etch
RIE texture

53. Selective Emitter Formation
100ohm / □
Emitter
High series resistance
between metal electrode and emitter
Base
20ohm / □
100ohm / □
Emitter
Reduce series resistance
between metal electrode and emitter
by using Selective Emitter
Base

54. Selective Emitter Formation
Schematic cross section of
selective emitter
Schematic of a one-step
selective emitter
fabricated by out-diffusion
via the gas phase of locally printed
rich P-source

55. Double Screen Printing
Diagrams of a conveltional grid electrode with a standard single printing and double printing

56. Local Back Surface Field

57. Local Back Surface Field
Making local BSF by using laser contact
Using Al-Si paste for making back contact
Decrease series resistance between rear side and contact
Make good ohmic contact

58. Double Passivation Layer for Rear side
UV/Violet
Visible
Red/IR
Typical statement of absorption of sunlight
Quantum Efficiency of absorption of sunlight

59. Double Passivation Layer for Rear side
Red/IR + +
Rear side of PV
Single Layer of BSR
( + )
Back Surface Reflection
Red/IR
Back Side Electrode
Two different layers at the backside:
Capture and recycle the photons
Reflects more light than the aluminium layer
Light reenters the silicon at low angle  light
bounces around inside
Rear side of PV +
Back Surface Passivation
First Layer of BSR
( - )
Back Surface Reflection
Second Layer of BSR
Back Side Electrode +

60. Back Contact Structure
Ribbon
( - ) charge
( + ) charge
Each cell has been connecting with ribbon indirectly
Each cell will have been connecting with ribbon directly
( + / - ) charge
Ribbon
( + ) charge
( - ) charge

61. Back Contact Structure
Metal Wrap Through
MWT cell
Easy to make modules with solar cells
Can reduce series resistance between cells
Removing shading area from front bus bar

62. 향후 추진 방향 mc-Si wafer RIE texture etch n+ selective emitter Efficiency
PECVD SiNx:H ARC on both sides
Local Al-BSF on rear side
Front grid double screen printing (~80 μm wide)
Double Passivation Layer
Back Contact
Structure
18%
Local
BSF
Double
Passivation
Layer
Selective
Emitter
Double
Screen
Printing
15%
RIE Etching
Process

63. 결 론