Lithium tantalate thin film infrared detector and manufacturing method

Abstract

The present invention relates to a lithium tantalate film infrared detector and the preparing method thereof. The invention comprises the following components: an infrared filtering window, a resonance chopped wave modulator, a focusing lens, a pyroelectric lithium tantalate film infrared measuring probe, a heat sink cavity, a preamplifier, a low-pass filter, an electric power and signal output interface, a casing and an environment temperature detecting filter. The method for preparing the detector comprises the following steps: selecting a substrate, growing a SiO2 layer on the front and back surface, depositing Si3N4 layer on the front surface in sequence, sputtering a Ti layer, sputtering a photoetching Pt electrode layer, producing a lithium tantalate film layer, depositing a phototeching Al electrode layer, growing a photoetching SiNX antireflection layer and sputtering a black layer to complete the double unit structure infrared probe. The focusing lens is coated with an anti-reflection film. The infrared window is pasted with a narrowband filtering film. The preamplifier is built with a JFET tube or operational amplifier. The low-pass filter is built with an operational amplifier. The resonance chopped wave modulator is driven by piezoelectricity or electromagnet, and the resonance frequency is 1Hz-1000Hz.

Description

technical field [0001] The invention belongs to the field of infrared detectors, and in particular relates to a non-refrigerated pyroelectric lithium tantalate film infrared detector and a manufacturing method thereof which detect infrared radiation in the wavelength range of 2-20 μm and are modulated by resonant chopping. Background technique [0002] The uncooled pyroelectric infrared detector works according to the pyroelectric effect, which means that when some crystal or film materials with pyroelectric characteristics are subjected to frequency-modulated infrared heat radiation, temperature changes will occur in the crystal or film. The electric dipole moment of its molecules will change accordingly, and the surface of the crystal or film will induce accumulated pyroelectric response charges due to the pyroelectric effect. [0003] Early photon-type infrared detectors, such as mercury cadmium telluride detectors, in order to improve the sensitivity of photon detectors ...

AI Technical Summary

Problems solved by technology

Therefore, the pyroelectric infrared sensor of bulk material is not suitable for high-performance pyroelectric infrared detection applications due to the limitations of geometric structure and thickness.

In addition, the existing pyroelectric infrared detectors still face three problems. The first is that the infrared radiation energy is usually very weak, and special structures need to be designed to effectively absorb it; the second is that the background light, ambient temperature Fluctuations will interfere with the output signal of the detector; the third is that shock or vibration will cause the detector to output a large interference signal, because usually pyroelectric materials have both pyroelectric and piezoelectric properties

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