Miao Fengjuan

An Array of One-Dimensional Porous Silicon Photonic Crystal Reflector Islands for a Far-Infrared Image Detector

With the aid of photolithography, an array of one-dimensional porous silicon photonic crystal reflector islands for a far infrared image detector ranging from 10 μm to 14 μm is successfully fabricated. Silicon nitride formed by low pressure chemical vapor deposition (LPCVD) was used as the masking layer for the island array formation. After etching, the microstructures were examined by a scanning electron microscope and the optical properties were studied by Fourier transform infrared spectroscopy, the result indicates that the multilayer structure could be obtained in the perpendicular direction via periodically alternative etching current in each pre-pattern. At the same time, the island array has a well-proportioned lateral etching effect, which is very useful for the thermal isolation in lateral orientation of the application in devices. It is concluded that regardless of the absorption of the deposition layer on the substrate, the localized photonic crystalline islands have higher reflectivity. The designed islands structure not only prevents the cracking of the porous silicon layers but is also useful for the application in the cold part for the sensor devices and the interconnection of each pixel.

Fabrication of arrays of one-dimensional porous silicon photonic crystal: Fabrication of arrays of one-dimensional porous silicon photonic crystal

With the aid of photolithography, arrays of one-dimensional porous silicon photonic crystals with the middle infrared mid-gap (lambda = 5,6,7,10 mu m) were fabricated successfully by the combination of microelectronic technique and the electrochemical etching method. For practical use, the roughness of the surface was improved by depositing a Si3N4 thin film with 5000 angstrom. Then their optical and roughness properties were characterized by FTIR and AFM, respectively. As a result of the synergetic effects rendered by heat isolation and high reflection properties, the array of the one-dimensional porous silicon photonic crystal exhibits feasibility as the substrate for pyroelectric infrared sensor.