图形化Silicon-on-Insulator衬底上分子束外延生长可动GaN微光栅的研究

GaN材料作为第三代半导体材料,具有宽禁带、直接带隙、耐腐蚀等优点,是一种非常有前景的MOEMS材料。由于GaN的刻蚀目前尚未成熟,因此图形化外延生长法是一种较好的选择。本文基于SOI(silicon-on-insulator)基片,利用硅的微加工技术和图形化GaN分子束外延生长工艺,设计并加工了工作在太赫兹波段的、可以在二维方向上运动的SOI基GaN光栅。光栅周期为16μm,光栅宽度为6μm,峰值位置为25.901μm。通过仿真优化,设计的微驱动器在水平电压220V时,水平方向上的位移为±7.26μm;垂直方向加200V电压时,垂直位移2.5μm。为了研究在图形化SOI衬底上外延生长的InGaN/GaN量子阱薄膜的光学性能,用激光拉曼光谱仪对薄膜进行了光致发光光谱实验。实验结果表明,InGaN/GaN量子阱薄膜具有良好的发光性能,其发光范围为350~500nm,覆盖了紫外光到黄绿光。由于局域态效应与禁带收缩的作用,随着环境温度由10K升高至室温,薄膜的PL光谱的峰位呈现"S"形变化趋势。

Movable GaN Membrane Micro-Grating on Patterned SOI Substrate Deposited with Molecular Beam Epitaxy

As the third generation of semiconductor material,GaN has many advantages,such as wide bandgap,direct band gap,corrosion resistance and so on.Also,GaN is a very promising material for MOEMS.Because the etching of GaN material is not mature,epitaxial growth on patterned substrate is more helpful for GaN/SOI device.A movable GaN grating on patterned SOI substrate was designed and fabricated with Si micromaching and molecular beam epitaxy process of GaN.The grating actuated by a SOI electrostatic comb-drive micro-actuator could move in two dimensional directions and it could be used as filter in Terahertz wavelength.The period and width of the grating is 16 and 6 μm,respectively.The resonant wavelength is 25.901 μm.An horizontal displacement of ±7.26 μm is obtained at 220 V of horizontal voltage with simulation.When the vertical voltage is 200 V,the displacement is 2.5 μm.The photoluminescence (PL) measurements of the deposited InGaN/GaN multiple quantum well on patterned SOI substrate are carried out with laser Raman spectrometer.The experimental results show that good optical property of the InGaN/GaN multiple quantum well.A wide emission wavelength from 350 to 500 nm is demonstrated.With the increase of temperature from 10 K to room temperature,the photoluminescence peak position appears a tendency of "S" shape because of the localized effect and band shrink in the InGaN/GaN quantum well.