Dede Didem, Glas Frank, Piazza Valerio, Morgan Nicholas, Friedl Martin, Güniat Lucas, Nur Dayi Elif, Balgarkashi Akshay, Dubrovskii Vladimir G, Fontcuberta I Morral Anna
Laboratory of Semiconductor Materials, Faculty of Engineering, Institute of Materials, EPFL, Lausanne, Switzerland.
Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, France.
Nanotechnology. 2022 Sep 8;33(48). doi: 10.1088/1361-6528/ac88d9.
Selective area epitaxy (SAE) provides the path for scalable fabrication of semiconductor nanostructures in a device-compatible configuration. In the current paradigm, SAE is understood as localized epitaxy, and is modelled by combining planar and self-assembled nanowire growth mechanisms. Here we use GaAs SAE as a model system to provide a different perspective. First, we provide evidence of the significant impact of the annealing stage in the calculation of the growth rates. Then, by elucidating the effect of geometrical constraints on the growth of the semiconductor crystal, we demonstrate the role of adatom desorption and resorption beyond the direct-impingement and diffusion-limited regime. Our theoretical model explains the effect of these constraints on the growth, and in particular why the SAE growth rate is highly sensitive to the pattern geometry. Finally, the disagreement of the model at the largest pitch points to non-negligible multiple adatom recycling between patterned features. Overall, our findings point out the importance of considering adatom diffusion, adsorption and desorption dynamics in designing the SAE pattern to create pre-determined nanoscale structures across a wafer. These results are fundamental for the SAE process to become viable in the semiconductor industry.
选择性区域外延（SAE）为以器件兼容配置可扩展制造半导体纳米结构提供了途径。在当前模式中，SAE被理解为局部外延，并通过结合平面和自组装纳米线生长机制进行建模。在此，我们以砷化镓SAE作为模型系统来提供一个不同的视角。首先，我们提供了退火阶段对生长速率计算有重大影响的证据。然后，通过阐明几何约束对半导体晶体生长的影响，我们证明了在直接碰撞和扩散限制 regime 之外，吸附原子解吸和再吸附的作用。我们的理论模型解释了这些约束对生长的影响，特别是为什么SAE生长速率对图案几何形状高度敏感。最后，模型在最大间距处的不一致表明图案化特征之间不可忽略的多个吸附原子循环。总体而言，我们的研究结果指出了在设计SAE图案以在整个晶圆上创建预定纳米级结构时考虑吸附原子扩散、吸附和解吸动力学的重要性。这些结果对于SAE工艺在半导体行业中可行至关重要。
