Microbolometer array with improved performance

摘要

According to one aspect, the invention relates to a microbolometer array for thermal detection of light radiation in a given spectral band, comprising a supporting substrate and an array of microbolometers (300) of given dimensions, arranged in an array. Each of said microbolometers comprises a membrane (301) suspended above said supporting substrate, said membrane consisting of an element (305) for absorbing the incident radiation and a thermometric element (304) in thermal contact with the absorber, electrically insulated from said absorber element. The absorber element comprises at least one first metal/insulator/metal (MIM) structure comprising a multilayer of three superposed films of submicron-order thickness i.e. a first metallic film (311), a dielectric film (310), and a second metallic film (309), said MIM structure being able to have a resonant absorption of said incident radiation at at least one wavelength in said spectral band. The area of the microbolometer pixel covered by said membrane (301) is less than or equal to half of the total area of the microbolometer pixel.

主权项

1. A microbolometer array for thermal detection of light radiation in a given spectral band, comprising a supporting substrate and an array of microbolometer pixels of given dimensions, wherein each microbolometer pixel comprises:
a membrane suspended above said supporting substrate by supporting elements, said membrane consisting of an element for absorbing the incident radiation and a thermometric element in thermal contact with the absorber, electrically insulated from said absorber element; elements for electrically connecting said thermometric element to the supporting substrate; thermally insulating arms arranged between the thermometric element and the supporting substrate; and wherein: the absorber element comprises at least one first metal/insulator/metal (MIM) structure comprising a multilayer of three superposed films of submicron-order thickness including a first metallic film, a dielectric film, and a second metallic film, said MIM structure being able to have a resonant absorption of said incident radiation at at least one resonant wavelength in said spectral band; at least one lateral dimension of said MIM structure is smaller than or equal to λr/2n where λr is the resonant wavelength and where n is the refractive index of the dielectric material of the dielectric film in said MIM structure; the lateral dimension of the MIM structure, the thickness of the dielectric film and the thicknesses of the first metallic film and second metallic film are determined as a function of the resonant wavelength and the refractive index of the dielectric material to have a maximum absorption at said resonant wavelength, resulting in an effective absorption area of said MIM structure at said resonant wavelength having at least one dimension of the order of the resonant wavelength; and the area of the microbolometer pixel covered by said membrane is less than or equal to half of the total area of the microbolometer pixel.