Fingerprint sensor and manufacturing method thereof

Abstract

The invention provides a fingerprint sensor and a manufacturing method thereof.The fingerprint sensor comprises a metal conducting layer, an interface dielectric layer formed on the metal conducting layer, a metal oxide layer formed on the metal conducting layer, a silicon-enriched dielectric layer formed on the metal oxide layer, and a transparent conducting layer formed on the silicon-enriched dielectric layer, wherein the silicon-enriched dielectric layer is used for sensing light and generating light current.Compared with the prior art, the metal oxide layer is additionally arranged below the silicon-enriched dielectric layer, the metal oxide layer is used as buffering to lower dark current, and the sensitivity of the fingerprint sensor is improved.In addition, when the chemical vapor deposition method is adopted for forming the silicon-enriched dielectric layer, plasma surface treatment is performed on the metal conducting layer synchronously so as to form the metal oxide layer, and therefore the existing PEP number will not be increased.

Description

technical field [0001] The invention relates to an optical sensor, in particular to a fingerprint sensor containing light sensing elements. Background technique [0002] With the continuous innovation of electronic products, in addition to simply viewing image data, the display panel is gradually added with a touch input function to become a human-computer interaction interface. In recent years, optical sensing elements are also gradually applied on display panels, for example, as fingerprint sensors. [0003] In the prior art, a relatively common fingerprint sensor structure includes a metal conductive layer (metalconductivelayer), an interfacial dielectric layer, a silicon dielectric layer SRO (such as SiO x ) and a transparent conductive layer (such as ITO). Wherein, the interface dielectric layer is located above the metal conductive layer, the silicon dielectric layer SRO is located above the metal conductive layer, and the transparent conductive layer is located abov...

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Problems solved by technology

Moreover, in order to improve the absorption capacity of the near-infrared light band, it is necessary to increase the concentration of germanium (Ge) in the silicon-rich dielectric layer SGRO, but with the increase of the concentration of germanium, more and more defects in the silicon-rich dielectric layer SGRO, resulting in dark The dark current, or leakage, is getting bigger and bigger

Although the leakage is reduced by stacking a silicon-rich dielectric layer SRO on the upper or lower surface of the silicon-rich dielectric layer SGRO as a buffer layer, the photosensitive layer at this time includes two, namely, the silicon-rich dielectric layer And the silicon dielectric layer, which makes spectrum adjustment more difficult, and also increases the number of photo-etching processes (photo-etching process, PEP), increasing the manufacturing cost

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