| 학회 | 한국재료학회 |
| 학술대회 | 2015년 봄 (05/14 ~ 05/15, 구미코) |
| 권호 | 21권 1호 |
| 발표분야 | A. 전자/반도체 재료 |
| 제목 | Y 도핑을 통한 ZrO2 박막 내 산소 정공 조절 및 전기적 특성 개선 |
| 초록 | With accelerated scaling down of integrated circuit, it is very challenged to employ metal-insulator-metal (MIM) capacitor with high capacitance density and low leakage current for dynamic random access memory (DRAM). Addressing this, there has been great attention for the investigation of novel high-k materials for high performance, based on conventional high-k dielectrics such as ZrO2 and HfO2. Among them, by the doping of transition metal such as Ti, Ta, and Ge or rare earth elements such as Y, La, and Ce, the electrical properties of host materials, ZrO2 and HfO2 are enhanced in aspects of dielectric constant and leakage current. Y doping into ZrO2 stabilizes the cubic phase of ZrO2 due to the introduction of oxygen vacancies (Vo) in films, and the cubic ZrO2 has much higher dielectric constant than monoclinic ZrO2. On the other hand, Vo in films generates the gap states in Eg, which contribute to leakage path for carriers. Proper control of the density of Vo in ZrO2 films by modulating Y concentration could be key component for both required capacitance density and leakage current of ZrO2-based DRAM capacitors. Though supercycle process of atomic layer deposition (ALD) enables us to easily modulate Vo density and Y doping concentration in films, there has been no attempt to control Vo density and Y concentration by using ALD. In this work, we investigated ALD Y doped ZrO2 with a variety of Y/(Y+Zr) compositions. 1.5 times higher dielectric constant and 100 times lower leakage currents of Y doped ZrO2 than those of ZrO2 were observed. These results are valuable, in that there has been no report on the process to enhance both dielectric constant and leakage currents, simultaneously. We fundamentally studied the reduced leakage current mechanism in two main aspects; a) trap gap site of Y-Vo defect and b) bandgaps depending on crystal structures. The study will be fundamentally and practically meaningful for the fabrication of future DRAM devices. |
| 저자 | 박보은1, 오일권1, David Thompson2, 이한보람3, 김형준1 |
| 소속 | 1연세대, 2Applied Materials, 3인천대 |
| 키워드 | ZrO<SUB>2</SUB>; Y doping; Oxygen vacancy; MIM; DRAM; |
