| 학회 | 한국재료학회 |
| 학술대회 | 2016년 가을 (11/16 ~ 11/18, 경주 현대호텔) |
| 권호 | 22권 2호 |
| 발표분야 | C. 에너지 재료 분과 |
| 제목 | Exfoliated sub 5 µm thick silicon foil by controlled exfoliation process |
| 초록 | Ultra-thin and kerf-less wafering technology has drawn great interests as a substrate for flexible electronics such as integrated circuits, photovoltaics and light emitting diode [1-3]. Recently, mechanical stress induced exfoliation process known as spalling was developed for fabrication of sub-50 µm thick flexible single crystal semiconductor substrates in wafer scale [1,4]. In the exfoliation process, initial crack formation inside semiconductor substrate has to be introduce by cost-effective method. At the same time, the exfoliated Si thickness that is propositional with stressor layer’s thickness has to be easily controlled [1,5]. In this work, we present a graded stressor thickness strategy for initial crack formation inside of semiconductor and controlling of exfoliated Si thickness. The stressor layer are selectively thick at the edge for spontaneous crack initiation in the Si mother wafer and controlled thickness at center for controlling of exfoliated Si thickness. The profile of stressor layer was easily controlled by adjusting electroplating current density from 5 to 40 mA/cm2. These approach enable to variation of thickness ratio (Stressor layer’s thickness ratio between edge and center area) from 1.5 to 2.7. The crack initiation condition was systematically analysis based on spalling theory [5]. The stressor layer thickness at edge has to be thicker than critical thickness about 39 µm with average residual stress of 414 MPa. The calculated minimum value of energy release rate Gm for crack initiation condition was 6.92 J/m2. And, the exfoliated Si thickness was extremely decreasing from 38 to 5 µm with 1 inch diameter by decreasing of stressor layer’s thickness from 26 to 14µm. We anticipate that this cost-effective and high-throughput thin wafering method will huge effect on the flexible electronic and solar cell industry. Reference [1] S. W. Bedell, K. Fogel, P. Lauro, D. Shahrjerdi, J. A. Ott, D. Sadana, J. Phys. D Appl. Phys. 46, 152002 (2013) [2] S. Saha, M. M. Hilali1, E. U. Onyegam1, D. Sarkar, D. Jawarani, R. A. Rao, L. Mathew, R. S. Smith, D. Xu, U. K. Das, B. Sopori and S. K. Banerjee, Appl. Phys. Lett. 102, 163904 (2013) [3] S. W. Bedell, C. Bayram, K. Fogel, P. Lauro, J. Kiser, J. Ott, Y. Zhu and D. Sadana, Appl. Phys. Express 6, 112301 (2013) [4] F. Dross, J. Robbelein, B. Vandevelde, E. Van Kerschaver, I. Gordon, G. Beaucarne, and J. Poortmans, Appl. Phys. A: Mater. Sci. Process. 89, 149 (2007) [5] Z. Suo, and J. W. Hutchinson, Int. J. Solids Struct. 25, 1337 (1989). |
| 저자 | 이용환, 오지훈 |
| 소속 | 한국과학기술원 |
| 키워드 | Spalling; Silicon; Flexible; Kerfless |
