Oxide Nano Electronics Lab., Laser Materials Processing Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, India.
Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India.
Nanoscale. 2023 May 11;15(18):8337-8355. doi: 10.1039/d3nr00909b.
Considering the excellent tunability of electrical and dielectric properties in binary metal oxide based multi-layered nanolaminate structures, a thermal atomic layer deposition system is carefully optimized for the synthesis of device grade AlO/TiO nanolaminates with well-defined artificial periodicity and distinct interfaces, and the role of process temperature in the structural, interfacial, dielectric and electrical properties is systematically investigated. A marginal increase in interfacial interdiffusion in these nanolaminates, at elevated temperatures, is validated using X-ray reflectivity and secondary ion mass spectrometry studies. With an increase in deposition temperature from 150 to 300 °C, the impedance spectroscopy measurements of these nanolaminates exhibited a monotonic increment in dielectric constant from ∼95 to 186, and a decrement in dielectric loss from ∼0.48 to 0.21, while the current-voltage measurements revealed a subsequent reduction in leakage current density from ∼2.24 × 10 to 3.45 × 10 A cm at 1 V applied bias and an improvement in nanobattery polarization voltage from 100 mV to 700 mV, respectively. This improvement in dielectric and electrical properties at elevated processing temperature is attributed to the reduction in impurity content along with the significant enhancement in sublayer densities and the conductivity contrast driven Maxwell-Wagner interfacial polarisation. Additionally, the devices fabricated at 300 °C exhibited a higher capacitance density of ∼22.87 fF μm, a low equivalent oxide thickness of ∼1.51 nm, and a low leakage current density of ∼10 A cm (at 1 V bias), making this nanolaminate a promising material for high-density energy storage applications. These findings highlight the ALD process temperature assisted growth chemistry of AlO/TiO nanolaminates for superior dielectric performance and multifaceted applications.
考虑到二元金属氧化物基多层纳米层结构中电和介电性能的优异可调性，精心优化了热原子层沉积系统，以合成具有明确定义的人工周期性和明显界面的器件级 AlO/TiO 纳米层，系统研究了工艺温度对结构、界面、介电和电性能的影响。使用 X 射线反射率和二次离子质谱研究验证了这些纳米层在高温下界面互扩散略有增加。随着沉积温度从 150°C 升高到 300°C，这些纳米层的阻抗谱测量显示介电常数从约 95 单调增加到 186，介电损耗从约 0.48 单调减小到 0.21，而电流-电压测量表明漏电流密度从约 2.24×10 减小到 3.45×10 A cm 在 1 V 施加偏压下，纳米电池极化电压分别从 100 mV 提高到 700 mV。在较高处理温度下，介电和电气性能的这种改善归因于杂质含量的减少以及亚层密度的显著提高和由 Maxwell-Wagner 界面极化引起的电导率对比。此外，在 300°C 下制造的器件表现出约 22.87 fF μm 的更高电容密度、约 1.51 nm 的低等效氧化物厚度和约 10 A cm 的低漏电流密度（在 1 V 偏压下），使这种纳米层成为高密度储能应用的有前途的材料。这些发现强调了 ALD 工艺温度辅助的 AlO/TiO 纳米层的生长化学，以实现卓越的介电性能和多方面的应用。
