臺灣博碩士論文加值系統

由於在常溫下擁有高熱電轉換效率，碲化鉍被視為最具有應用價值的熱電材料之一，近年來對碲化鉍的研究皆著重於提高其熱電優值(Figure-of-merit)以及對應之製備方法，僅少數探討隨後組裝成熱電晶片會面臨之封裝製程問題。然而，因為熱電晶片係由大量 p 及 n 型熱電模組藉由銲料與銅基板串連而成，已有文獻指出銲料中的 Sn 與碲化鉍中的 Te 元素反應極容易生成 SnTe 介金屬化合物(Intermetallic compound, IMC)， 由此可知，銲點可靠度將是影響熱電裝置使用壽命，以及其實際應用時熱電轉換效率的重要因素。

本實驗分別以奈米結構及目前最常被用來製造熱電材料之區域重熔技術製成的塊材 p 型及 n 型 Bi2Te3 基材與 SAC405 銲料反應，實驗結果發現 塊材 p 型 Bi2Te3，與 SAC405 在 120、150 及 200℃熱處理下，反應生成之 SnTe 層皆比奈米 p 型反應偶厚；而 n 型塊材 Bi2Te3 與 SAC405 在 120 及 150℃熱處理時之 SnTe 層較奈米反應厚，但反應溫度提高到 200℃後，由於奈米反應偶中 BixTey 之大量產生，使得奈
米反應偶之 IMC 總厚度較塊材反應偶厚。

若將區域重熔 Bi2Te3 以垂直或平行層狀方向與純錫銲料迴銲，經 150℃熱處理後發現非常有趣的現象：碲化鉍原有的層狀結構會影響區域重熔之單晶碲化鉍與錫的界面反應，尤其在 p 型模組非常明顯，以垂直或平行層狀方向會生成不同型態且非常厚的 SnTe 層，其中垂直方向之 IMC 大於平行方向，平行方向生成之 SnTe 層具有(220)的優選方向。當熱處理時間拉長後，Sn3Sb2 條紋 IMC 開始生成，其因層狀方向差異而有不同方向的分布。使用自熔的 Bi2Te3 基材與純錫銲料反應則無上述之方向性差異，且 p 型 IMC 厚度較區域重熔模組薄很多。

Because of no moving parts, small size and noiseless operation, thermoelectric (TE) materials have drawn much attention and be wildly used recently, among which, bismuth Telluride is best known for its great thermoelectric ability of converting heat to electricity at room temperature. Lots of researches are emphasizing on improving the conversion efficiency of TE materials, i.e. figure-of-merit, but only few are on the solder joints reliability of the thermoelectric device. Actually, “reliability” is the key point to prolong the lifetime of a thermoelectric device and so to improve the conversion efficiency due to huge amount of solder joints in the TE device.

In this research, we use nano-structured and zone-melted Bi2Te3 substrates to join with SAC405 solder.We found zone-melted p-type Bi2Te3/SAC405 interface formed thicker SnTe than nano-structured p-type Bi2Te3/SAC405 at 120, 150 and 200℃. In n-type Bi2Te3/SAC405 interface, zone-melted samples formed thicker SnTe at 120 and 150℃. But after increasing aging temperature to 200℃, IMC in nano structured n-type Bi2Te3/SAC405 became thicker. It’s because of the BixTey formation between SnTe and n-type Bi2Te3 substrate.

Knowing that bismuth telluride is a layered structure compound, we use pure Sn solder to join the zone-melted Bi2Te3 substrate in a direction perpendicular or parallel to
its layer direction. The IMC is mainly composed by SnTe, but the IMC thickness and its morphology are quite different. SnTe in parallel joining direction had (220) preferential
orientation. After long period of thermal treatment, Sn3Sb2 strips started to appear inside the SnTe layer and their distributions depended on substrate’s orientation. Compare to self-made Bi2Te3/Sn reaction couple, IMCs were not concernd with substrate’s orientation, and IMCs in self-made p-type Bi2Te3/Sn interface were much thinner than those in zone-melted reaction couples.

摘要 ..................................................... I
Abstract ............................................... III
目次 .................................................... IV
表目錄 .................................................. VI
圖目錄 ................................................. VII
1.緒論 ................................................... 1
1.1 前言 ................................................. 1
1.2 研究目的 ............................................. 1
2.文獻回顧 ............................................... 3
2.1熱電材料介紹 ........................................... 3
2.1.1 三大熱電效應 ...................................... 4
2.1.2 熱電材料之熱電轉換效率描述 ......................... 5
2.1.3 碲化鉍(Bi2Te3)系熱電材料........................... 7
2.2熱電材料之製程與結構 ................................... 9
2.2.1 常見熱電材料製程 ................................. 10
2.2.2 奈米結構熱電材料 ................................. 16
2.3界面反應 ............................................. 19
2.3.1 銲料與熱電材料之界面反應 ......................... 19
2.3.2 擴散阻障層與熱電材料之界面反應 .................... 26
3.實驗方法 .............................................. 34
3.1材料製備 ............................................. 34
3.1.1 Bi2Te3 熱電材料 ................................. 34
3.1.2 基材切割 ........................................ 36
3.2Bi2Te3 熱電材料/銲料反應偶 ............................ 36
3.2.1 奈米及塊材 Bi2Te3/SAC405 ......................... 36
3.2.2 不同方向塊材及合金 Bi2Te3/Sn ..................... 37
3.3試片分析 ............................................. 38
3.3.1 橫截面之金相分析 ................................. 38
3.3.2 XRD 繞射圖譜分析 ................................. 39
4.結果與討論 ............................................. 40
4.1奈米及塊材 Bi2Te3 基材與 SAC405 銲料界面反應 ........... 40
4.1.1 奈米 Bi2Te3 基材與 SAC405 銲料之界面反應 ......... 40
4.1.2 塊材(Bulk)Bi2Te3 基材與 SAC405 銲料之界面反應 .... 46
4.1.3 奈米及塊材 Bi2Te3 基材與 SAC405 銲料界面反應動力學比較 ......................................................... 50
4.2不同 Bi2Te3 基材方向與純錫銲料界面反應 ................. 55
4.2.1 區域重熔 Bi2Te3 基材與純錫銲料之界面反應 .......... 55
4.2.2 自熔 Bi2Te3 基材與純錫銲料之界面反應 .............. 59
4.2.3 區域重熔與合金 Bi2Te3/Sn 反應機制及動力學比較 ..... 60
5.結論 .................................................. 64
6.參考文獻 .............................................. 65

[1] G. J. Snyder and E. S. Toberer, “Complex Thermoelectric Materials”, Nature Materials, Vol. 7, pp. 105-114 (2008).
[2] A. J. Minnich, M. S. Dresselhaus, Z. F. Ren and G. Chen, “ Bulk Nanostructured Thermoelectric Materials: Current Research and Future Prospects”, Energy & Environmental Science, Vol. 2, pp. 466-479 (2009).
[3] S. W. Chen and C. N. Chiu, “Unusual Cruciform Pattern Interfacial Reactions in Sn/Te Couples”, Scripta Materialia, Vol. 56, pp. 97-99 (2007).
[4] H. J. Goldsmid, “The Electrical Conductivity and Thermoelectric Power of Bismuth Telluride”, Proceedings of the Physical Society, Vol. 71, pp. 633-646 (1958).
[5] M. Zebarjadi, K. Esfarjani, M. S. Dresselhaus, Z. F. Ren and G. Chen, “Perspectives on Thermoelectrics: From Fundamentals to Device Applications”, Energy & Environmental Science, Vol. 5, pp. 5147-5162 (2012).
[6] M. S. Dresselhaus, G. Chen, M. Y. Tang, R. Yang, H. Lee, D. Wang, Z. Ren, J. P.Fleurial and P. Gogna, “New Directions for Low-Dimensional Thermoelectric Materials”, Advanced Materials, Vol. 19, pp. 1043-1053 (2007).
[7] D. Kraemer, B. Poudel, H. P. Feng, J. C. Caylor, B. Yu, X. Yan, Y. Ma, X. Wang, D.Wang, A. Muto, K. McEnaney, M. Chiesa, Z. Ren and G. Chen, “High-Performance Flat-Panel Solar Thermoelectric Generators with High Thermal Concentration”, Nat Mater, Vol. 10, pp. 532-538 (2011).
[8] 黃振東、徐振庭，「熱電材料」，科學發展期刊，第 486 期，第 48-53 頁 (2013)。
[9] D. Teweldebrhan, V. Goyal, M. Rahman and A. Balandin, “Atomically-Thin Crystalline Films and Ribbons of Bismuth Telluride”, Applied Physics Letters, Vol.96, pp. 0513107 (2010).
[10] Y. Feutelais, B. Legendre, N. Rodier and V. Agafonov, “A Study of the Phases in the Bismuth - Tellurium System”, Materials Research Bulletin, Vol. 28, pp.591-596 (1993).
[11] D. Teweldebrhan, V. Goyal and A. Balandin, “Exfoliation and Characterization of Bismuth Telluride Atomic Quintuples and Quasi-Two-Dimensional Crystals”, Nano Letters, Vol. 10, pp. 1209-1218 (2010).
[12] L. D. Zhao, B. P. Zhang, J. F. Li, H. L. Zhang and W. S. Liu, “Enhanced Thermoelectric and Mechanical Properties in Textured N-type Bi2Te3 Prepared by Spark Plasma Sintering”, Solid State Sciences, Vol. 10, pp. 651-658 (2008).
[13] X. Yan, B. Poudel, Y. Ma, W. S. Liu, G. Joshi, H. Wang, Y. Lan, D. Wang, G. chen and Z. F. Ren, “Experimental Studies on Anisotropic Thermoelectric Properties and Structures of N-Type Bi2Te2.7Se0.3” , Nano Letters, Vol. 10, pp. 3373-3378 (2010).
[14] M. H. Francombe, “Structure-Cell Data and Expansion Coefficients of Bismuth Telluride”, British Journal of Applied Physics, Vol. 9, pp. 415-417 (1958).
[15] J. Jiang, L. Chen, S. Q. Bai, Q. Yao and Q. Wang, “Thermoelectric Properties of P-type (Bi2Te3)x(Sb2Te3)1−x Crystals Prepared via Zone Melting”, Journal of Crystal Growth, Vol. 277, pp. 258-263 (2005).
[16] H. P. Ha, D. B. Hyun, J. Y. Byun, Y. J. Oh and E. P. Yoon, “Enhancement of the Yield of High-Quality Ingots in the Zone-Melting Growth of P-type Bismuth Telluride Alloys”, Journal of Materials Science, Vol. 37, pp. 4691-4696 (2002).
[17] M.H. Ettenberg, J.R. Maddux, P.J. Taylor, W.A. Jesser and F.D. Rosi, “Improving Yield and Performance in Pseudo-Ternary Thermoelectric Alloys (Bi2Te3)(Sb2Te3)(Sb2Se3)”, Journal of Crystal Growth, Vol. 179, pp. 495-502 (1997).
[18] Y. Ma, Q. Hao, B. Poudel, Y. Lan, B. Yu, D. Wang, G. Chen and Z. Ren, “Enhanced Thermoelectric Figure-of-Merit in p-Type Nanostructured Bismuth Antimony Tellurium Alloys Made from Elemental Chunks”, Nano Letters, Vol. 8, pp. 2580-2584 (2008).
[19] B. Poudel, Q. Hao, Y. Ma, Y. Lan, A. Minnich, B. Yu, X. Yan, D. Wang, A. Muto, D. Vashaee, X. Chen, J. Liu, M. S. Dresselhaus, G. Chen and Z. Ren, “High-Thermoelectric Performance of Nanostructured Bismuth Antimony Telluride Bulk Alloys”, Science, Vol. 320, pp. 634-638 (2008).
[20] A. J. Minnich, M. S. Dresselhaus, Z. F. Ren and G. Chen, “Bulk Nanostructured Thermoelectric Materials: Current Research and Future Prospects”, Energy & Environmental Science, Vol. 2, pp.466-479 (2009).
[21] Y. Lan, B. Poudel, Y. Ma, D. Dresselhaus, G. Chen and Z. Ren, “Structure Study of Bulk Nanograined Thermoelectric Bismuth Antimony Telluride”, Nano Letters, Vol. 9, pp. 1419-1422 (2009).
[22] C. N. Chiu, C. H. Wang and S. W. Chen, “Interfacial Reactions in the Sn-Bi/Te Couples”, Journal of Electronic Materials, Vol. 37, pp. 40-44 (2008).
[23] C. N. Liao and C. H. Lee, “Suppression of Vigorous Liquid Sn/Te Reactions by Sn–Cu Solder Alloys”, Journal of Material Research, Vol. 23, pp. 3303-3308 (2008).
[24] C. N. Liao and Y. C. Huang, “Effect of Ag Addition in Sn on Growth of SnTe Compound during Reaction between Molten Solder and Tellurium”, Journal of Materials Research, Vol. 25, pp. 391-395 (2010).
[25] C. H. Lee, W. T. Chen and C. N. Liao, “Effect of Antimony on Vigorous Interfacial Reaction of Sn-Sb/Te Couples”, Journal of Alloys and Compounds, Vol. 509, pp. 5142-5146 (2011).
[26] C. N. Liao, C. H. Lee and W. J. Chen, ” Effect of Interfacial Compound Formation on Contact Resistivity of Soldered Junctions Between Bismuth Telluride-Based Thermoelements and Copper”, Electrochemical and Solid-State Letters, Vol. 10, pp. 23-25 (2007).
[27] F. Li, X. Huang, W. Jiang and L. Chen, “Microstructure and Contact Resistivity of (Bi, Sb)2Te3/Sb Interface”, AIP Conference Proceedings, Vol. 1449, pp. 458-462 (2012).
[28] S. W. Chen, H. J. Wu, C. F. Chang and C. Y. Chen, “Reaction Evolution and Alternating Layer Formation in Sn/(Bi0.25Sb0.75)2Te3 and Sn/Sb2Te3 Couples”, Journal of Alloys and Compounds, Vol. 553, pp. 106-112 (2013).
[29] H. Zhang, H.Y. Jing, Y.D. Han, L.Y. Xu and G. Q. Lu, “Interfacial Reaction Between N- and P-type T hermoelectric Materials and SAC305 Solders”, Journal of Alloys and Compounds, Vol. 576, pp. 424-431 (2013).
[30] W. P. Lin, D. E. Wesolowski and C. C. Lee, “Barrier/Bonding Layers on Bismuth Telluride (Bi2Te3) for High Temperature Thermoelectric Modules”, Journal of
Materials Science: Materials in Electronics, Vol. 22, pp. 1313-1320 (2011).
[31] Y. C. Lan, D. Z. Wang, G. Chen and Z. F. Ren, “Diffusion of Nickel and Tin in P-Type (Bi,Sb)2Te3 and N-Type Bi2(Te,Se)3 Thermoelectric Materials”, Applied Physics Letters, Vol. 92, pp. 101910-3 (2008).
[32] O. D. Iyore, T. H. Lee, R. P. Gupta, J. B. White, H. N. Alshareef, M. J. Kim and B.E. Gnade, “Interface Characterization of Nickel Contacts to Bulk Bismuth Tellurium Selenide”, Surface and Interface Analysis, Vol. 41, pp.440-444 (2009).
[33] T.Y. Lin, C.N. Liao, and A. T. Wu, “Evaluation of Diffusion Barrier between Lead-Free Solder Systems and Thermoelectric Materials”, Journal of Electronic Materials, Vol. 41, pp. 153-158 (2012).
[34] R. P. Gupta, O. D. Iyore, K. Xiong, J. B. White, K. Cho, H. N. Alshareef and B. E. Gnade, “Interface Characterization of Cobalt Contacts on Bismuth Selenium Telluride for Thermoelectric Devices”, Electrochemical and Solid-State Letters, Vol. 12, pp. H395-H397 (2009).
[35] R. P. Gupta, K. Xiong, J. B. White, K. Cho, H. N. Alshareef and B. E. Gnade, “Low Resistance Ohmic Contacts to Bi2Te3 Using Ni and Co Metallization”, Journal of The Electrochemical Society, Vol. 157, pp. H666-H670 (2010).
[36] H. C. Pan and T. E. Hsieh, “Diffusion Barrier Characteristics of Electroless Co(W,P) Thin Films to Lead-Free SnAgCu Solder”, Journal of The Electrochemical Society, Vol. 158, pp. 123-129 (2011).
[37] C. Y. Ko and A. T. Wu, “Evaluation of Diffusion Barrier between Pure Sn and Te”, Journal of Electronic Materials, Vol. 41, pp. 3320-3324 (2012).
[38] 柯昌延，「錫碲擴散偶之擴散阻障層界面反應」，碩士論文，國立中央大學化學工程與材料工程學系所，桃園 (2012)。
[39] J. Y. Song, J. Yu and T. Y. Lee, “Effect of Reactive Diffusion on Stress Evolution in Cu-Sn Films”, Scripta Materialia, Vol. 51, pp. 167-170 (2004).
[40] A. G. Beattie, “Temperature Dependence of the Elastic Constants of Tin Telluride”, Journal of Applied Physics, Vol. 40, pp. 4818 (1969).
[41] H. F. Zou, H. J. Yang and Z. F. Zhang, “Morphologies, Orientation Relationships and Evolution of Cu6Sn5 Grains Formed Between Molten Sn and Cu Single Crystals”, Acta Materialia, Vol. 56, pp. 2649-2662 (2008).
[42] D. A. Porter, K. E. Easterling and M. Y. Sherif, “Phase Transformations in Metals and Alloys”, New York, CRC Press, pp. 143-144 (2008).