| 학회 | 한국재료학회 |
| 학술대회 | 2020년 가을 (11/18 ~ 11/20, 휘닉스 제주 섭지코지) |
| 권호 | 26권 1호 |
| 발표분야 | A. 전자/반도체 재료 분과 |
| 제목 | Selective and localized nanosecond UV laser annealing for amorphous TiO2 thin film: Transform to rutile phase, higher dielectric constant and improve electrical properties. |
| 초록 | Laser annealing process has been widely used in various industries including semiconductor, photovoltaic, and flat panel display manufacturing. The most common approach is the line beam excimer laser annealing process on amorphous silicon to crystalize it while prevents thermal damage to the substrate underneath. The benefit of excimer is higher pulse energy with shorter wavelength but in the other hands it requires higher cost of ownership due to gas consumption, frequent maintenances and laser itself is bulky. With continuous evolves of nanosecond solid state laser technologies, the average output power is scaled up to 100W for single mode, Q switched 355nm UV wavelength with hundreds kHz pulse repetition rates. This higher power higher repetition rates features with TEM00 single mode is broadening its application bandwidth and enables uniform heat treatment on thin film to transform its phases. Another benefit is its smaller architecture and low cost of ownership which are inevitable to utilize its application as real life technics. TiO2, titanium dioxide thin film performs as a capacitor dielectric for dynamic random-access memory (DRAM) and resistance switching material in resistance random-access memory (RRAM). TiO2 has three tetragonal phases including anatase, rutile, and brookite, and we are interested in rutile phase TiO2 which has 90-170 dielectric constant. Rutile phase TiO2 is only grown on lattice matching substrate, for example ruthenium, and this specific crystallographic phase requirement for growth severely limits its utilization and application prospective. The other technique is furnace heat treatment and it is proven to transform amorphous TiO2 to rutile phase. However, the furnace heat treatment will also change not only TiO2 but its substrates properties as well, which is never willing to have. In this study, we attempted to deposit amorphous TiO2 thin film by atomic layer deposition on TiN, which is the most widely used metal electrode in various electronics, and used nanosecond Q-switched UV laser from MKS Spectra-Physics for selective, localized laser annealing process. Applied D.O.E beam shaping optics to generate flat top beam for uniform intensity distribution at workpiece and high-speed X-Y galvanometer scanners for fast process achievement. To analyze and collect data from experiments, atomic force microscopy (AFM) and X-ray diffraction (XRD) were used for surface morphology study and crystallographic changes, respectively. The electrical property was also evaluated. |
| 저자 | 안재원1, 전우진2 |
| 소속 | 1경희대, 2MKS Instrument Korea |
| 키워드 | Nanosecond UV laser annealing; dynamic random access-memory; high-k material; capacitor dielectric; atomic layer deposition; Ru; TiO2; rutile phase |
