Zhang Guohe, Lai Junhua, Su Yali, Li Binhong, Li Bo, Bu Jianhui, Yang Cheng-Fu
School of Microelectronics, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
School of Mechanical Engineering, Xi'an Shiyou University, Xi'an 710065, Shaanxi, China.
Materials (Basel). 2019 Aug 15;12(16):2601. doi: 10.3390/ma12162601.
The silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) suffer intensive self-heating effects due to the reduced thermal conductivity of the silicon layer while the feature sizes of devices scale down to the nanometer regime. In this work, analytical models of thermal conductivity considering the self-heating effect (SHE) in ultra-thin body fully depleted (UTB-FD) SOI MOSFETs are presented to investigate the influences of impurity, free and bound electrons, and boundary reflection effects on heat diffusion mechanisms. The thermal conductivities of thin silicon films with different parameters, including temperature, depth, thickness and doping concentration, are discussed in detail. The results show that the thermal dissipation associated with the impurity, the free and bound electrons, and especially the boundary reflection effects varying with position due to phonon scattering, greatly suppressed the heat loss ability of the nanoscale ultra-thin silicon film. The predictive power of the thermal conductivity model is enhanced for devices with sub-10-nm thickness and a heavily doped silicon layer while considering the boundary scattering contribution. The absence of the impurity, the electron or the boundary scattering leads to the unreliability in the model prediction with a small coefficient of determination.
随着器件特征尺寸缩小至纳米量级，绝缘体上硅（SOI）金属氧化物半导体场效应晶体管（MOSFET）由于硅层热导率降低而遭受强烈的自热效应。在这项工作中，提出了考虑超薄体全耗尽（UTB-FD）SOI MOSFET自热效应（SHE）的热导率分析模型，以研究杂质、自由电子和束缚电子以及边界反射效应对热扩散机制的影响。详细讨论了具有不同参数（包括温度、深度、厚度和掺杂浓度）的薄硅膜的热导率。结果表明，与杂质、自由电子和束缚电子相关的热耗散，特别是由于声子散射导致的随位置变化的边界反射效应，极大地抑制了纳米级超薄硅膜的散热能力。在考虑边界散射贡献的情况下，对于厚度小于10nm且硅层重掺杂的器件，热导率模型的预测能力得到增强。杂质、电子或边界散射的缺失会导致模型预测的不可靠性，决定系数较小。
