Dynamics of SiO2 Buried Layer Removal from Si-SiO2-Si and Si-SiO2-SiC Bonded Substrates by Annealing in Ar
Dynamics of SiO2 Buried Layer Removal from Si-SiO2-Si
and Si-SiO2-SiC Bonded Substrates by Annealing in Ar
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Ar 中退火去除 Si-SiO2-Si 和 Si-SiO2-SiC 粘合基板中 SiO2 埋层的动力学
DOI：
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发表时间：
2014
影响因子：
2.1
通讯作者：
J. Olsson
中科院分区：
文献类型：
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作者：
L.;S. Rubino;Ö. Vallin;J. Olsson
碳化硅衬底上的硅可能是高功率和射频硅器件的理想选择。当通过晶片键合制成时，这种混合晶片包含具有差的热特性的中间二氧化硅层，其可以通过在惰性气氛中的高温退火来去除。为了了解这一过程的动力学，在1100°C至1200°C的温度范围内研究了从Si-SiO2-Si和Si-SiO2-SiC衬底上去除2.4 nm厚的SiO2层。通过透射电子显微镜，电子能量损失谱，二次离子质谱，和椭圆偏振仪，退火前后的基板进行了分析。对于小于2.4 nm的氧化物厚度，氧化物去除的活化能估计为6.4 eV，大于报道的较厚氧化物去除的活化能（4.1 eV）。在相同条件下，SiO2层变得不连续。在时域中，可以区分三个步骤：体扩散，体扩散与空隙形成，体扩散与解体。空洞的形成，占主导地位，在这里，有一个能量的成本，可以解释较大的激活能。在长时间退火后剩余的氧化物对应于一层氧原子。
Silicon-on-silicon-carbide substrates could be ideal for high-power and radiofrequency silicon devices. Such hybrid wafers, when made by wafer bonding, contain an intermediate silicon dioxide layer with poor thermal characteristics, which can be removed by high-temperature annealing in an inert atmosphere. To understand the dynamics of this process, removal of 2.4-nm-thick SiO2 layers from Si-SiO2-Si and Si-SiO2-SiC substrates has been studied at temperatures ranging from 1100°C to 1200°C. The substrates were analyzed by transmission electron microscopy, electron energy-loss spectroscopy, secondary-ion mass spectroscopy, and ellipsometry, before and after annealing. For oxide thickness less than 2.4 nm, the activation energy for oxide removal was estimated to be 6.4 eV, being larger than the activation energy reported for removal of thicker oxides (4.1 eV). Under the same conditions, the SiO2 layer became discontinuous. In the time domain, three steps could be distinguished: bulk diffusion, bulk diffusion with void formation, and bulk diffusion with disintegration. The void formation, predominant here, has an energetic cost that could explain the larger activation energy. The oxide remaining after prolonged annealing corresponds to one layer of oxygen atoms.