Dielectrics for narrow bandgap III-V devices
Dielectrics for narrow bandgap III-V devices
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发表时间：
2018-10
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通讯作者：
O. Vavasour
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作者：
O. Vavasour
锑化铟是一种窄禁带半导体或材料，其特性使其成为中红外光电子学、超高速电子学和新兴的基于自旋的量子技术的理想选择。其实际应用的一个重要限制是缺乏用于表面钝化和栅极控制的电介质技术。MOS电容器的建模和分析技术已被定制为InSb和验证，包括非抛物线带结构模型和氧化物电容提取方法。高场效应，如齐纳隧道效应和碰撞电离，已被建模，以确定材料掺杂的限制（<1016 cm-3）和量化效应已被类似地建模，以验证其对表征和分析的影响。为了研究InSb/Al 2 O3 MOS电容器的一系列电介质淀积工艺，研制了一种新型的InSb/Al 2 O3 MOS电容器测试结构。发现使用HCl的湿化学处理产生InCl 3表面层，但仅当用异丙醇稀释和冲洗时。该层与+0.79V的平带电压偏移相关联。发现HCl处理降低滞后电压，但不显著影响其它品质因数。原位等离子体预处理被发现会导致MOSCAP结构的恶化，特别是增加的DC漏电流。对金属化后退火进行了研究，确定最佳处理为300°C左右，1小时。在400°C或更高温度下，MOSCAP行为发生破坏，显示出频率分散增加和潜在的顶部型行为。一些AlInSb层的生长，但提供有限的信息的Al组合物的效果，与层的生长方法和材料应变的显着影响。还审查了替代方案。氮化铝提供略有改善的滞后，但略有增加的界面陷阱密度，而HfO 2产生的劣化的所有因素的优点，特别是滞后电压。这些结果为进一步的工艺开发和集成到改进的FET/二极管器件结构提供了基础。
Indium antimonide is a narrow bandgap semiconduct or material with properties that make it ideal for mid-infrared opto electronics, ultra-high speed electronics and emerging spin-based quantum technologies. A significant limitation to its practical application is the lack of a dielectric technology for surface passivation and gate control. Modelling and analysis techniques for MOS capacitors have been tailored to InSb and verified, including nonparabolic band structure models and oxide capacitance extraction methods. High-field effects, such as Zener tunnelling and impact ionisa-tion, have been modelled to identify limitations on material doping (<1016 cm-3) and quantisation effects have been similarly modelled to verify their impact on characterisation and analysis. InSb/Al2O3 MOS capacitor test structures have been fabricated to investigate a series of dielectric deposition processes. Wet chemical treatments using HCl were found to produce an InCl3 surface layer, but only if diluted in and rinsed with isopropanol. This layer was associated with a flat band voltage shift of +0.79V.HCl treatment was found to reduce hysteresis voltage but not significantly affect other figures of merit. In-situ plasma pretreatments were found to cause deterioration in MOSCAP structures, in particular increased DC leakage current. Post-metallisation annealing was investigated and optimum treatments determined to be around 300°C, 1 hr. At 400°C or greater, MOSCAP behaviour broke down, showing increased frequency dispersion and potential shift top-type behaviour. Some AlInSb layers were grown but provided limited information on the effect of Al composition, with layers significantly affected by growth methods and material strain. Alternative dielectrics were also examined. AlN offered slightly improved hysteresis but slightly increased interface trap density, whereas HfO2 produced dete-rioration in all figures of merit, particularly hysteresis voltage. These results pro- vide a foundation for further process development and integration into improved FET/diode device structures.