Nanoimprint Lithography And Its Application On Metal-Wire Nanograting And Semiconductor Laser Diodes

Device with minimum feature size of nano dimension is the trend of microelectronic technology. Traditional lithography has meet great challenges when patterning structures into nano scale. And the electronic beam lithography and x-ray lithography, etc. are too expensive to be adopted for mass production. The semiconductor industry is looking for the next generation lithography with sub-100nm minimum feature size. Nanoimprint lithography (NIL) is just the next generation lithography with sub-100nm resolution, high-throughput and low cost. NIL is based on physical deformation of the resist rather than modification of the resist chemical structure through UV light or X-ray radiation.This thesis explores the application of nanoimprint lithography and related issues. The applications include metal-wire nanograting for polarizing beam splitter, DFB grating for InP-based 1310nm and 1550nm wavelength semiconductor laser diodes.Fabrication of high quality and low cost nanoimprint stamp is a key technology for popularize the NIL technology. In this paper, we studied the fabrication technology of silicon and quartz stamp for metal-wire nanograting and semiconductor DFB gratings. The line width of the grating is about 100nm. The scanning electron microscope images of the fabricated stamps show good uniformity with sufficiently low line edge roughness.In metal-wire nanograting, we present a new type of embedded metal-wire nanograting. In which the metal wires were embedded under the trenches of the substrate, and a cladding layer was deposited on the surface of the trenches to protect the metal-wire grating. The fabricated novel nanograting has high extinction ratio (45dB and 28dB respectively for transmitted TM component and reflected TE component), and low insertion loss (0.15dB and 0.11dB respectively for TM and TE component) for optical communication wavelength.In 1310nm wavelength semiconductor laser diodes, we present the design and fabrication of high speed and wide temperature range uncooled 1310nm DFB lasers. With the optimization of the strained-layer multi-quantum wells in the active region, the surrounding graded-index separated-confinement-heterostructure waveguide layers, together with the optimization of the detuning and coupling coefficient of the DFB grating, high directly modulation bandwidth of 16GHz at room temperature and wide working temperature range from -40℃to 85℃were obtained. The device is suitable as light source of high-bit-rate optical transmitters with small size and reduced cost.In 1550nm wavelength semiconductor laser diodes, we present the design and fabrication of multi-wavelength DFB semiconductor laser diodes for DWDM system. Thirteen laser diodes, with wavelength interval of 0.8nm ranging from 1545nm to 1555nm and SMSR over 40dB, were fabricated using nanoimprint technology on one wafer with one process. This makes it possible to produce low cost and high quality DFB lasers for DWDM system.