半导体/超晶格分布布拉格反射镜(DBR) 的分子束外延生长

用分子束外延技术(MBE)生长了以GaAs/AlAs超晶格替代AlxGa1-xAs所形成的P型半导体/超晶格分布布拉格反射镜(DBR)．此分布布拉格反射镜的反射谱中心波长为850nm．由实验表明，19个周期的反射镜获得了高达99％以上的高反射率．与此同时，采取自行设计的二次钨丝掩膜质子注入法制成15μm×15μm的正方形电流注入区，以此测定P型反射镜的串联电阻，克服了湿化学腐蚀法中腐蚀深度不易控制及侧面同时被腐蚀的缺点，实验得出此P型反射镜的串联电阻仅为50Ω左右．在生长过程中，发现在只含一个铝源的分子束外延生长系统中，生长这种半导体/超晶格反射镜相对其他半导体/半导体反射镜要节省很多外延生长时间，因此较适合应用于多层结构的光电器件中．

Semiconductor/Superlattice Distributed Bragg Reflector Grown by Molecular Beam Epitaxy

By replacing the AlxGa1-xAs with GaAs/AlAs superlattice,the p type semiconductor/superlattice distributed Bragg reflector(DBR) has been grown by molecular beam epitaxy (MBE)．The center wavelength of the DBR reflection spectrum is about 850nm;and the 19-period DBR has the high reflectivity of 99.5%．Using twice self-designed tungsten filament mask and proton implantation method，we fabricate a square current flowing area size of 15μm×15μm with which the series resistance of the p type DBR is measured about 50 Ohm.Therefore,the semiconductor/superlattice DBR has proved to be of low series resistance and high reflectivity,which applies to the optoelectronic devices such as vertical-cavity surface-emitting lasers (VCSEL's)，which need high optical feed back and low power consumption.Dwing to the omission of the interface structures between two semiconductor heterointerfaces for the purpose of decreasing the series resistance in DBR,the structure and the fabrication of the DBR are simplified and successfully applied in the optoelectronic devices with complicated structure．In this method the depth of implantation is controllable;and the side etching happened in wet chemical etching is avoided．In the process of growth,the MBE system with a single Al source is found to be of less growth time with this kind of semiconductor/superlattice DBR,so it is suitable for the optoelectronic devices with multiple-layer structures．