Chen Baoqin

An All-Optical Diode Based on Plasmonic Attenuation and Nonlinear Frequency Conversion

We present the design of an all-optical diode in a metal-dielectric structure where plasmonic attenuation and quasi-phase-matching are harnessed to greatly improve its performance. Due to the asymmetric design of the second-order nonlinear coefficient, different incident directions will ignite different plasmonic nonlinear processes, which compensate or accelerate plasmonic attenuation. As a result, a unidirectional output of plasmonic signal is achieved. This designed all-optical diode shows advantages of low power consumption, short sample length, high isolation contrast, wide acceptance of structural and initial conditions, and tunable unidirectionality, and becomes of practical interest.

Fabrication of 11-nm-Wide Silica-Like Lines Using X-Ray Diffraction Exposure

Fine silica-like lines with 11 nm width are successfully fabricated using x-ray Fresnel diffraction exposure. X-rays pass a mask of 175-nm-wide lines and 125-nm-wide spaces and form sharp peaks on a wafer coated with a layer of hydrogen silsesquioxane resist (HSQ). By precisely controlling the mask-wafer gap at 10 μm using the laser interferogram method, the fine structures are defined on HSQ. Experimental images are reproduced by a simulation using the one-dimensional beam propagation method. This lithographic technique presents a novel and convenient way to fabricate fine silica-like structures and devices in nano-optical and nanoelectronic applications.

Three-wavelength generation from cascaded wavelength conversion in monolithic periodically poled lithium niobate

Tunable coherent emission is generated in a single-pass, cascaded wavelength conversion process from mode-locked laser-pumped monolithic periodically poled lithium niobate (PPLN). Three ranges of wavelength, including visible output from 628 nm to 639 nm, near-infrared output from 797 nm to 816 nm, and mid-infrared output from 3167 nm to 3459 nm, were obtained from the monolithic PPLN, which consists of a 10-mm section for 532-nm-pumped optical parametric generation (OPG) and a 7-mm section for 1064-nm-pumped sum frequency generation (SFG). A pump-to-signal conversion efficiency of 23.4% for OPG at 50 °C and a quantum efficiency of 26.2% for SFG at 200 °C were obtained.

Study of process of HSQ in electron beam lithography

As a kind of inorganic negative-tone resist in electron beam lithography, hydrogen silsesquioxane(HSQ) has a high pattern resolution of about 5 nm, but the poor sensitivity limits its extensive application in the field of micro-fabrication. Its very difficult to fabricate the high aspect-ratio dense resist pattern for HSQ because of backscattering electrons and proximity effect. The methods by optimizing process condition are proposed to improve the contrast of graphic structure of HSQ resist and restrain electron beam proximity effect at the same time. On 450nm thick resist layer, HSQ resist pillar array pattern with 5 aspect-ratio under 50kv voltage and HSQ resist mesh pattern structure with 9 aspect-ratio under 100kv voltage can been achieved with optimization of process condition.

The sub-micron fabrication technology

Electron beam lithography, X-ray lithography and etching technology are introduced in this paper. The submicron and nanometer fabrications are playing an ever-increasing role in science and technology. For e-beam lithography, the resist process, proximity effect correction and mix & match technologies are investigated. 0.15 /spl mu/m GaAs PHEMT devices are successfully fabricated by employing X-ray lithography. Finally, 100 nm pattern is etched by ICP.

A method to restrain the charging effect on an insulating substrate in high energy electron beam lithography

Pattern distortions caused by the charging effect should be reduced while using the electron beam lithography process on an insulating substrate. We have developed a novel process by using the SX AR-PC 5000/90.1 solution as a spin-coated conductive layer, to help to fabricate nanoscale patterns of poly-methyl-methacrylate polymer resist on glass for phased array device application. This method can restrain the influence of the charging effect on the insulating substrate effectively. Experimental results show that the novel process can solve the problems of the distortion of resist patterns and electron beam main field stitching error, thus ensuring the accuracy of the stitching and overlay of the electron beam lithography system. The main characteristic of the novel process is that it is compatible to the multi-layer semiconductor process inside a clean room, and is a green process, quite simple, fast, and low cost. It can also provide a broad scope in the device development on insulating the substrate, such as high density biochips, flexible electronics and liquid crystal display screens.

Design, Fabrication and Test of a Soft X-Ray Even-Order Transmission Grating

Most transmission gratings in the x-ray region work with their first orders and dispersion is limited by the line density achievable with current fabrication technology. We present a novel design of a two-dimensional x-ray transmission grating. The grating works with higher dispersion using its second orders, and the influence from first and third orders can be suppressed. A grating according to the novel design is fabricated and its diffraction performance is tested in comparison with a traditional x-ray transmission grating with the same line density. The novel grating could be especially useful when high dispersion is desired while the fabrication of high-density gratings becomes more difficult.

High performance 70 nm CMOS device and key technologies

The fabrication of the high performance 70 nm CMOS device has been successfully explored. Some innovation technologies such as 3 nm nitrided gate oxide, dual poly-Si gate electrode, lateral local super-steep retrograde channel doping using heavy ion implantation, Ge PAI plus LEI forming 40 nm ultra-shallow S/D extension, thin and low resistance Ti-salicide and Co/Ti-salicide etc. are investigated. By these innovations in technologies, high performance 70 nm CMOS devices with excellent SCE and good driving ability have been fabricated successfully. The 57 stage unloaded 100 nm CMOS ring oscillator circuits exhibiting delay 23.8 ps/stage at 1.5 V, and 17.5 ps/stage and 12.5 ps/stage at 2 V and 3 V respectively are achieved.