Infrared detector chip for increasing capacitance density

Abstract

The present invention discloses an infrared detector chip for increasing capacitance density, comprising a pixel array and a capacitor array required for a readout circuit. The capacitor array is positioned above and / or below the pixel array. The pixel array comprises M rows and N columns of pixel units. The capacitor array comprises A rows and N / A columns of capacitor units, and each column of pixel units corresponds to one capacitor unit in the capacitor array. The row directions and the column directions of the capacitor array and the pixel array are the same. The length of the capacitor units in the row direction is equal to the length of A pixel units in the row direction. The infrared detector chip for increasing capacitance density provided by the present invention expands the capacitance between single metal layers into multiple layers, thereby increasing capacitance density. Meanwhile, the capacitor units are distributed above and below the array and the width of the capacitorunits is increased, thereby improving the performance matching between column readout circuits and finally enhancing the performance of the entire chip.

Description

technical field [0001] The invention relates to the field of infrared detectors, in particular to an infrared detector chip with increased capacitance density. Background technique [0002] As the infrared detector array becomes larger and larger, even though the area of ​​a single pixel unit is shrinking, the chip area is also increasing with the increase of the area of ​​the pixel array. A large number of capacitor structures will be used in the infrared detector reading circuit, including AD / DA, integrator, sample / hold and other modules, which will need to use larger capacitors. At this time, the capacitor area and its matching gradually become the product and process design. Especially when the chip size is close to the maximum size of a single exposure in lithography, in order not to exceed this size and the overall cost considerations, a compromise has to be made in the selection of the capacitance area. Reducing the capacitance area will easily lead to a decrease in c...

AI Technical Summary

Problems solved by technology

A large number of capacitor structures will be used in the infrared detector reading circuit, including AD / DA, integrator, sample / hold and other modules, which will need to use larger capacitors. At this time, the capacitor area and its matching gradually become the product and process design. Especially when the chip size is close to the maximum size of a single exposure in lithography, in order not to exceed this size and the overall cost considerations, a compromise has to be made in the selection of the capacitance area. Reducing the capacitance area will easily lead to a decrease in chip performance. decline

[0003] Existing infrared detector chips include a pixel array and readout circuits located at both ends of the pixel array, as shown in the attached figure 1 As shown, the pixel array includes pixel units 1 in M ​​rows and N columns, and each column of pixel units corresponds to a readout circuit, which includes a capacitor unit 2. With the improvement of chip integration, the area of ​​a single pixel unit also increases. Smaller and smaller, so that the area of ​​the capacitor unit corresponding to each column is also smaller and smaller. The reduction in the area of ​​the capacitor unit, on the one hand, makes the size of the pattern smaller, resulting in a large error in the size of the pattern after photolithography and etching, causing the row The matching between the capacitance and the readout circuit becomes worse; on the other hand, the reduction of the capacitance area also reduces the capacitance density in the chip, so that the detection signal in the infrared detector cannot be read out in time and effectively, which affects the detection device performance

Capacitor units in the prior art have the disadvantage of small capacitance density in addition to their small area. The structures forming capacitors in the prior art are all formed by single-layer metal and through-hole connections, and the through-holes are in the horizontal section. Point structure, due to the small relative area between adjacent through holes, the capacitance value formed by it is also small, which cannot make full use of the limited capacitance area

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