| 학회 | 한국재료학회 |
| 학술대회 | 2016년 가을 (11/16 ~ 11/18, 경주 현대호텔) |
| 권호 | 22권 2호 |
| 발표분야 | C. 에너지 재료 분과 |
| 제목 | An Ultrathin Si Film Formation by the Silicon on Nothing Technology for High Performance Flexible and Semitransparent Electronic Devices |
| 초록 | A Semitransparent and flexible electronics have attracted intensive attention for use in a variety of applications such as see-through displays, photovoltaics, wearable devices, and other areas. Organic semiconductors are commonly used as an active material for flexible devices owing to its inherent flexibility as well as optical properties. However, the low thermal budget and instability of organic substrates have limited its usage in high performance electronic devices. The ultrathin single crystal Si is a good alternative to organic substrates because Si wafers thinned down to sub-micrometers can offer mechanical flexibility and optical semitransparency with its innate high electrical properties. The silicon on nothing (SON) technology is favorable to fabricate an ultrathin and flexible single crystal (100) Si foil on a wafer scale substrate. The SON structure can be obtained by reorganization of a well-ordered cylindrical pores in hydrogen annealing. At high temperature, cylindrical pores are evolved into thin Si layer and empty voids by surface diffusion. The thin SON layer can be easily released from the mother wafer by applying external stress owing to the empty voids. Here, we present a cost-effective approach for manufacturing highly uniform ultrathin (100) Si film based on the SON technology. In this work, well-controlled and scalable cylindrical nanopores with aspect ratio up to 7 were realized via nanoimprint lithography (NIL) and deep reactive ion etching. By adjusting aspect ratio of initial nanopores, we successfully fabricated SON layer with thickness of 330 to 470 nm on a wafer-scale substrate. In addition, we study the formation and removal of oxygen-related defects during hydrogen annealing for improving uniformity of Si layer. Through a systematic investigation, we successfully suppressed oxygen-related defects on the SON layer by modifying gas transport mechanisms during annealing. Finally, by contacting and releasing the PDMS pad onto the SON layer, we successfully transferred defect-free, flexible and wafer-scale Si film with a thickness of 470 nm on a PDMS substrate. The transferred Si film on the PDMS shows optical transmittance of 30~70 % in visible and near infrared light. |
| 저자 | 박상현1, 이용환1, 위정섭2, 오지훈1 |
| 소속 | 1KAIST, 2KRISS |
| 키워드 | <P>silicon on nothing; flexible; semitransparent; thin film; nanoimprint</P> |
