Studies of High Quality GaAs Layers Heteroepitaxially Grown on Si Substrates by Microchannel Epitaxy and Fabrication of Laser Diodes

在硅衬底上生长III-V族材料是制造光电集成电路（OEIC）的关键技术。尽管人们对在Si上生长III-V族材料进行了大量的研究，但III-V族材料与Si衬底之间较大的晶格失配和热膨胀系数的巨大差异仍然带来高位错密度（~10 cm）和层内强残余应力。 III-V族材料中的位错会严重恶化器件特性及其寿命，尤其是在光学器件中，因此，为了获得高性能和商业可靠性的光学器件，需要进一步提高结晶度。微通道外延（MCE）是一种通过SiO2D2薄膜中的开口（称为“微通道”）横向生长薄层的新技术。在MCE中，外延关系通过微通道转移到生长层，但除了狭窄的微通道之外，位错等缺陷不会继续。因此，MCE在克服异质外延中的上述困难方面具有非常大的潜力。MCE被应用于Si衬底上无位错GaAs层的生长。通过优化生长条件，使 MCE 层的宽度与厚度之比（W/T 比）最大化，获得了非常宽的无位错区域，最大可达 100 μm。空间分辨光致发光测量表明，MCE 层的光学质量几乎与同质外延生长的层相同。尝试在MCE层上制作垂直腔面发射激光器。结果，实现了激光器的优异光学质量，显示了电流注入光输出的模拟发射。激光器制造工艺的优化将实现基本OEIC。

Growth of III-V materials on Si substrates is a key technology for fabricating opto-electronic integrated circuits (OEICs). Though a lot of studies about the growth of III-V materials on Si have been carried out, a large lattice mismatch and a big difference in the thermal expansion coefficient between Ill-V materials and Si substrates still bring high dislocation density (〜10ィイD16ィエD1 cmィイD1-2ィエD1) and strong residual stress in the layers. The dislocations in the Ill-V materials strongly deteriorate the device characteristics and their lives especially in optical devices, therefore, further crystallinity improvement is necessary to obtain optical devices with high performance and commercial reliability.Microchannel epitaxy (MCE) is a new technology to grow thin layers laterally through an opening in SiOィイD22ィエD2 film, which is called as "microchannel". In MCE, epitaxial relationship is transferred through a microchannel to the grown layer but the defects such as dislocations are not continued except a narrow microchannel. Therefore, MCE has a very-high potentiality for overcoming the above-mentioned difficulties in heteroepitaxy.MCE was applied to the growth of dislocation-free GaAs layers on Si substrates. By optimizing the growth conditions for maximizing the ratio of the width of a MCE layer to the thickness (W/T ratio), very wide dislocation-free regions, which were as large as 100 μm, were consequently obtained, Spatially resolved photoluminescence measurements showed that the optical quality of the MCE layers was almost the same as that of a homoepitaxially grown ones. The vertical cavity surface-emitting laser was tried to fabricate on the MCE layer. As the result, an excellent optical quality of the laser, which shows a simulated emission on the light output by current injection, was achieved. An optimization of the fabrication process of the lasers will bring to the realization of an elemental OEIC.