RF Magnetron Sputtering법에 의해 저온 증착한 (Ba,Sr)TiO₃ 박막의 전기적 특성

Abstract

세라믹 (????)TiO₃타겟을 이용하여 RF magnetron sputtering 법으로 Pt/Ti/SiO₂/Si기 위에 300℃이하의 저온에서 BST 박막을 증착하였다. 본 연구에서는 증착변수인 기판온도와 양의 기판 DC bias 가 박막의 물성 및 전기적 특성에 미치는 영향을 주로 살펴보았다. 기판의 온도와 인가된 양의 기판 DC bias가 증가할수록 증착된 BST 박막의 결정성이 증가하였다. 증착된 박막은 타겟 조성보다 Ba Sr의 양이 결핍되었지만 다결정상의 BST가 형성되었으며 증착 중에 양의 기판 DC bias를 인가하면 박막의 방향성 성장을 촉진시켜 박막의 성장속도와 결정성이 향상되었다. 100kHz에서의 유전울 및 유전손실은 기판온도가 증가함에 따라 20∼82와 2.6∼6.5%로 증가하였고 양의 기판 DC bias를 인가하면 유전율과 유전선실이 약간 감소하였다. 그러나 기판온도와 양의 기판 DC bias가 증가할수록 박막의 누설전류를 감소하였다.

(Ba,Sr)TiO₃(BST) thin films were deposited on Pt/Ti/SiO₂/Si substrates at low temperatures below 300℃ by reactive RF magnetron sputtering methods. The electrical properties of the deposited films were investigated by controlling deposition parameters such as substrate temperature and positive substrate DC bias. The crystallinity of the BST film increased with increasing substrate temperature and positive substrate DC bias. The amounts of Ba and "Sr in the film, however, were less than those of a target. With increasing substrate temperature and positive substrate DC bias, the deficiency of Ba and Sr in the film was decreased. Dielectric constant and dielectric loss measured at 100kHz were increased from 20to 82and from 2.6 to 6.5%, respectively, with increasing substrate temperature in the range of 80~300℃, but were decreased a little with the positive substrate DC bias. The leakage current density of BST thin film capacitors was reduced with increasing substrate temperature and positive substrate DC bias.

(Ba,Sr)TiO₃(BST) thin films were deposited on Pt/Ti/SiO₂/Si substrates at low temperatures below 300℃ by reactive RF magnetron sputtering methods. The electrical properties of the deposited films were investigated by controlling deposition parameters such as substrate temperature and positive substrate DC bias. The crystallinity of the BST film increased with increasing substrate temperature and positive substrate DC bias. The amounts of Ba and "Sr in the film, however, were less than those of a target. With increasing substrate temperature and positive substrate DC bias, the deficiency of Ba and Sr in the film was decreased. Dielectric constant and dielectric loss measured at 100kHz were increased from 20to 82and from 2.6 to 6.5%, respectively, with increasing substrate temperature in the range of 80~300℃, but were decreased a little with the positive substrate DC bias. The leakage current density of BST thin film capacitors was reduced with increasing substrate temperature and positive substrate DC bias.