Chiappim William, Watanabe Marcos, Dias Vanessa, Testoni Giorgio, Rangel Ricardo, Fraga Mariana, Maciel Homero, Dos Santos Filho Sebastião, Pessoa Rodrigo
i3N, Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Laboratório de Sistemas Integráveis, Escola Politécnica da Universidade de São Paulo (USP-SP), 05508-010 São Paulo, Brazil.
Nanomaterials (Basel). 2020 Feb 17;10(2):338. doi: 10.3390/nano10020338.
In this paper, we report the plasma-enhanced atomic layer deposition (PEALD) of TiO and TiO/AlO nanolaminate films on p-Si(100) to fabricate metal-oxide-semiconductor (MOS) capacitors. In the PEALD process, we used titanium tetraisopropoxide (TTIP) as a titanium precursor, trimethyl aluminum (TMA) as an aluminum precursor and O plasma as an oxidant, keeping the process temperature at 250 °C. The effects of PEALD process parameters, such as RF power, substrate exposure mode (direct or remote plasma exposure) and AlO partial-monolayer insertion (generating a nanolaminate structure) on the physical and chemical properties of the TiO films were investigated by Rutherford backscattering spectroscopy (RBS), Raman spectroscopy, grazing incidence X-ray diffraction (GIXRD), and field emission scanning electron microscopy (FESEM) techniques. The MOS capacitor structures were fabricated by evaporation of Al gates through mechanical mask on PEALD TiO thin film, followed by evaporation of an Al layer on the back side of the Si substrate. The capacitors were characterized by current density-voltage (J-V), capacitance-voltage (C-V) and conductance-voltage (G-V) measurements. Our results indicate that RF power and exposure mode promoted significant modifications on the characteristics of the PEALD TiO films, while the insertion of AlO partial monolayers allows the synthesis of TiO/AlO nanolaminate with well-spaced crystalline TiO grains in an amorphous structure. The electrical characterization of the MOS structures evidenced a significant leakage current in the accumulation region in the PEALD TiO films, which could be reduced by the addition of partial-monolayers of AlO in the bulk of TiO films or by reducing RF power.
在本文中，我们报道了在p型硅（100）上通过等离子体增强原子层沉积（PEALD）制备TiO和TiO/Al₂O₃纳米层状薄膜以制造金属氧化物半导体（MOS）电容器。在PEALD过程中，我们使用四异丙醇钛（TTIP）作为钛前驱体，三甲基铝（TMA）作为铝前驱体，O等离子体作为氧化剂，并将工艺温度保持在250°C。通过卢瑟福背散射光谱（RBS）、拉曼光谱、掠入射X射线衍射（GIXRD）和场发射扫描电子显微镜（FESEM）技术研究了PEALD工艺参数，如射频功率、衬底暴露模式（直接或远程等离子体暴露）和Al₂O₃部分单层插入（生成纳米层状结构）对TiO薄膜物理和化学性质的影响。通过在PEALD TiO薄膜上通过机械掩膜蒸发Al栅极，然后在硅衬底背面蒸发Al层来制造MOS电容器结构。通过电流密度-电压（J-V）、电容-电压（C-V）和电导-电压（G-V）测量对电容器进行表征。我们的结果表明，射频功率和暴露模式对PEALD TiO薄膜的特性产生了显著影响，而插入Al₂O₃部分单层可以合成具有在非晶结构中排列良好的结晶TiO晶粒的TiO/Al₂O₃纳米层状结构。MOS结构的电学表征表明，PEALD TiO薄膜在积累区域存在显著的漏电流，通过在TiO薄膜主体中添加Al₂O₃部分单层或降低射频功率可以降低漏电流。
