Research on Fundamentals of Opt-Electronic Integral Circuit on Silicon Substrate

本研究的目的是建立一种在硅衬底上制造光波导的基本技术。基础技术建立后的最终目标是开发一种新型的光电集成电路。假设硅衬底阳极氧化制备的多孔硅氧化形成的SiO_2区域为芯层和包层材料。本实验主要是通过对硅衬底进行阳极氧化制备多孔硅层。为了制造波导，孔隙率必须达到55%，以便在氧化过程中材料的体积膨胀完全填充孔隙。为了使杂质掺杂对折射率的调节有效，需要在核心区有较大的孔径。另一方面，包层区域不需要掺杂杂质，孔的尺寸也不需要太大。采用含HF的电解液，研究了硅片的阳极氧化过程。使用高浓度HF电解液时，多孔硅的厚度没有变化，但孔隙尺寸增大。高电流密度的氧化不改变孔的大小，但使多孔硅变厚。即使在零电流密度下，多孔硅也能溶解在电解液中，并且随着阳极氧化时间的延长，多孔硅的孔径和厚度都增加。虽然光波导的最终形态尚未成型，但根据本研究获得的数据，可以通过调整包层区阳极氧化后电解液的HF浓度和调节电流密度来控制孔形状的分布。硅衬底光波导制备技术建立后，由于易于获得大尺寸、高质量的硅晶片，将应用于各种光集成电路。光电集成电路也将采用硅器件技术来实现。作为光电集成电路的有益应用实例，提出了一种平面型多层结构光电集成神经网络电路的新结构。少

The purpose of this research is to establish a fundamental technique for the fabrication of optical waveguides on a silicon substrate. The final target after the establishment of the fundamental technique is to develop a new type of opt-electronic integrated circuit. A SiO_2 region formed by the oxiddation of porous silicon which is prepared by the anodization of the silicon substrate is assumed to be the core and cladding material.The main experiment is the preparation of porous silicon layers by the anodization of silicon substrate. In order to fabricate a waveguide, the porosity must be 55% so that the pores are completely filled by the volume expansion of material during the oxidation. The larger pore size is required in core region so that the impurity doping to adjust the refractive index is effective. On the other hand, the impurity doping is not necessary in the cladding region and the size of pore need not so large.The anodization process of silicon wafer was studied by using … More electrolyte containing HF. Using high HF cncentration electrolyte, the thickness of porous silicon does not change but the size of pore increases. The andization with high current density does not change the pore size but gives thicker porous silicon. The porous silicon dissolves into electrolyte even at zero current density, and both the pore size and the thickness of porous silicon increase as increases the anodization time.Although the final form of the optical waveguide has not yet fabricated, it will be possible to control the distribution of pore shape by adjusting the HF concentration of the electrolyte after the anodizaiton of cladding region and adjusting the current density by referring the data obtained in this research.Optical waveguides on siliocn substrate will be applied to various optical integrated circuit after the establishment of the fabrication technology because it is easy to get a large silicon wafer with high quality. Opt-electronic integrated circuits will also be realized by using silicon device technology. As an example of useful application of opt-electronic integrated circuits, a new structure of planer type multi-layer structured opt-electronic integrated neural network circuit has been proposed. Less