1. Green Technology Research Center Droop, ESD and Heat dissipation of Flip-Chip Power LEDs Prof. Liann-Be Chang Vice Dean & Director Engineering College Green Technology Research Center (GTRC)

2. Page  2 Green Technology Research Center Outline  Epitaxial technology  LED process technology  Flip Chip technology

3. Page  3 Green Technology Research Center MOCVD 磊晶設備 2 sets of MOCVD ( Nippon Sanso) 1 set of MOCVD ( Aixtron)

4. Page  4 Green Technology Research Center MOCVD 附屬設備 氮氣儲存房 層流台＆防潮櫃 特殊氣體房 氫氣儲存房 JPC 廢氣處理塔 廢氣處理塔

5. Page  5 Green Technology Research Center MOCVD 附屬量測設備 金相顯微鏡 高解析度 X 光繞射儀 可對磊晶片做 初步的表面分析 可快速對成長完之磊晶片做精確 的晶格結構分析

6. Page  6 Green Technology Research Center 化合物半導體製程無塵室

7. Page  7 Green Technology Research Center 綠色科技研究中心製程實驗室

8. Page  8 Green Technology Research Center 圖形化基板技術

9. Page  9 Green Technology Research Center LED 晶粒製程設備 Flip-Chip BonderWafer Bonding Bonder

10. Page  10 Green Technology Research Center Wire & Bump Bonder

11. Page  11 Green Technology Research Center LED 標準亮度量測系統 IS-250 ( 直徑 25cm) Keythley2420

12. Page  12 Green Technology Research Center 積分球燈具量測系統 SLM-20T ( 直徑 50cm) Agilent E3634A (50V;4A)

13. Page  13 Green Technology Research Center LED 光學量測系統 穿透反射量測儀 LED 遠場角量測儀

14. Page  14 Green Technology Research Center 紅外線熱影像量測儀 SC620 顯微鏡頭 :25um 測溫範圍 :-40~1500 o

15. Page  15 Green Technology Research Center LED 熱阻量測分析儀 Operating Current (mA) Forward Volt. (V F ) ΔT j-a ( o C)

16. Page  16 Green Technology Research Center  Apparatus(1F)3 sets of MOCVD ( Nippon Sanso + Aixtron) MOCVD

17. Page  17 Green Technology Research Center  Apparatus(9F) Measurement Equipments Device Process Equipments Clean Room

18. Page  18 Green Technology Research Center Methodology used in GTRC to Improve LED Performance MethodEnhance luminance Thermal reliability ESD Epi- growth Patterned Sapphire Substrate Ⅴ ZnO Template on Sapphire Ⅴ DH LED prevent droops Ⅴ. Chip process Surface textured Ⅴ Bottom Metal reflector Ⅴ Micro Channel/Photonic crystal Ⅴ Top TCO layer ⅤⅤ Bonding Wafer bonding ⅤⅤⅤ Flip- chip bonding ⅤⅤⅤ

19. Page  19 Green Technology Research Center MOCVD epitaxial technology

20. Page  20 Green Technology Research Center Low Temperature n-GaN LED Structure Inserting LT n-GaN layer

21. Page  21 Green Technology Research Center Optical & Electrical Characteristic n-GaN thickness 20 mA 0 nm5.595E-7 30 nm6.093E-7 50 nm6.364E-7 70 nm6.744E-7 140 nm4.966E-7

22. Page  22 Green Technology Research Center Pattern Sapphire Substrate LEDs 平台 (flat-top) 三角形 (pyramid)

23. Page  23 Green Technology Research Center Optical & Electrical Characteristic 2 times Sample Ave. center wavelength at 20 mA Ave. LOP (mcd) at 20 mA conventional464.080.8 三角形 (pyramid) 465.65147.51 平台 (flat-top) 467.72180.74 74% up

24. Page  24 Green Technology Research Center Epitaxial Growth : LED on ZnO Template Sapphire LED structure ZnO buffer (300 nm)

25. Page  25 Green Technology Research Center Improving the luminescence by selective activation or ion implantation

26. Page  26 Green Technology Research Center Reflectance and Contact Resistance of Ni/Ag-Based Metal Contacts on p-Type GaN Ni/Ag Ni/Ag/Au Ni/Ag/Ti/Au

27. Page  27 Green Technology Research Center Micro Channel LED

28. Page  28 Green Technology Research Center Electron confine (blocking) effect For sample B, except an additional 20-nm-thick p-type Al0.25Ga0.75N EBL inserted between the active layer and the p-type AlGaN/GaN superlattice structure to enhance the electron- blocking effect, the other growth conditions and structures were the same as those for sample A. The light-output power of sample B increases more rapidly and becomes greater than that of sample A in the measurement range from 25 to 130 A/cm 2. Applied Physics Express 3 (2010)

29. Page  29 Green Technology Research Center Electron decelerating effect Appl. Phys. Lett. (2010).

30. Page  30 Green Technology Research Center Efficiency droop research by double-hetero structure LED

31. Page  31 Green Technology Research Center Wafer Bonding Technology At present, wafer bonding technology is used widely

32. Page  32 Green Technology Research Center The proposed Flip The proposed Flip-Chip Structure on MOS submount use MOS heat sink & ESD protecting substrates heat flow can through the submount with high thermal conductivity material high reflect material heat

33. Page  33 Green Technology Research Center Core Technology : Pick/Place and U.S. Bonding

34. Page  34 Green Technology Research Center Top View of Flip-Chip Power LED

35. Page  35 Green Technology Research Center PN Junction & MOS Structure Submount Conventional FCLED on PN Junction Submount The Proposed FCLED on MOS Protective Submount

36. Page  36 Green Technology Research Center ESD Handling Capability Non flip-chipped LED FC-LED on PN junction

37. Page  37 Green Technology Research Center ESD Handling Capability FC-LED on MOS Zc = 1/jωc is small for large capacitance submount

38. Page  38 Green Technology Research Center Output Power Intensity Non Flip-chip LED luminance would be saturated at a large current injection The best performance was flip- chip LED on AlN submount because AlN had higher thermal conductivity than Si

39. Page  39 Green Technology Research Center Flip-Chip AC-LED We can easily design an 24 V AC-circuit directly on the submount through FC technology

40. Page  40 Green Technology Research Center Different LED chip on Si substrate thermal analysis Si Substrate Thermal Image CLED FCLED (20 gold bumps) VLED CLEDFCLED VLED 69 o C 78 o C

41. Page  41 Green Technology Research Center Remote Phosphor

42. Page  42 Green Technology Research Center  Researchers from Taiwan’s Chung-Gung University have determined the diffusion mechanism into GaAs….  Sep,2007

43. Page  43 Green Technology Research Center Thank you for your attention