针对锗芯光纤内pn结器件的热处理制备和改性问题，本文选择光纤包层和纤芯交界区域这一特殊位置，以一种典型的p型锗材料中的受主元素铝作为掺杂元素，使用Materials studio软件建立掺铝（Al）的锗（Ge）/二氧化硅（SiO2）界面模型，从不同温度出发模拟锗芯光纤热处理过程中该区域的动力学过程。选择热处理温度分别为500℃、600℃、660℃、700℃、727℃、827℃的6组样品，分析了不同温度下掺杂原子Al的均方根位移、扩散系数、掺Al的Ge/SiO2结构晶胞参数变化。研究发现：当温度处于500℃、600℃、660℃时，Al原子在结构中的扩散程度逐渐减小；当温度处于700℃、727℃和827℃时，Al原子的扩散程度增大。该结果初步说明了由温度升高引起的掺杂原子位移会使晶体中原子位置发生变化，从而造成锗芯光纤内pn结性能的改变。此外，研究了掺Al的Ge/SiO2结构的应力变化以及应力-应变关系，发现锗芯光纤内应力表现为拉应力，该拉应力随温度的变化趋势与结构晶胞参数变化相印证，且不同温度下的应力与应变成正比。在500℃、600℃、660℃、700℃、727℃温度下，温度越高，弹性模量越小；当温度达到827℃，弹性模量增大。本研究结果对半导体芯光纤内结型器件的热处理优化改性具有重要意义。
For the heat treatment preparation and modification of pn junction devices in germanium-core fibers, this study selected the core-cladding junction region as the research focus and adopted a typical p-type germanium material with the host element aluminum as the doping element. An aluminum (Al)-doped germanium (Ge)/silicon dioxide (SiO2) interface model was established by using Materials studio software. Dynamic simulations of the heat treatment process for pn junctions in germanium-core fibers were conducted at different temperatures, specifically 500 ℃, 600 ℃, 660 ℃, 700 ℃, 727 ℃, and 827 ℃. The mean square displacement of the dopant atoms Al, diffusion coefficients, and cellular parameter changes of the Al-doped Ge/SiO2 structure were analyzed at different temperatures. It was observed that the diffusion of Al atoms in the structure decreased progressively at 500 ℃, 600 ℃, and 660 ℃, while it increased at 700 ℃, 727 ℃, and 827 ℃. This phenomenon preliminarily indicates the displacements of dopant atoms induced by the temperature increase lead to changes of atomic positions in the crystals and ultimately result in the alteration of the properties of pn junctions within germanium-core fibers. Moreover, the stress variations and stress-strain relationship of the Al-doped Ge/SiO2 structure were investigated. It was found that the internal stress in germanium-core optical fiber is manifested as tensile stress and the trend of tensile stress with temperature is consistent with the changes in structural cell parameters. Additionally, the stress-strain relationship was observed to be proportional at different temperatures. For temperatures of 500 ℃, 600 ℃, 660 ℃, 700 ℃, and 727 ℃, the elastic modulus decreases as the temperature rises; however, when the temperature reached 827 ℃, the elastic modulus increased. These findings provide important insights for optimizing the heat treatment modification of junction-type devices in semiconductor-core fibers.
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