Vertical color filter sensor group and semiconductor integrated circuit fabrication method for fabricating same

Abstract

A vertical color filter sensor group, formed on a substrate (preferably a semiconductor substrate) by a semiconductor integrated circuit fabrication process, and including at least two vertically stacked, photosensitive sensors. Other aspects of the invention are arrays of such vertical color filter sensor groups, and methods for fabricating such vertical color filter sensor groups and arrays thereof. In some embodiments, the sensor group is a block of solid material having a readout surface. At least two vertically stacked sensors are formed in the block and a trench contact is provided between one of the sensors and the readout surface.

Description

technical field [0001] The present invention relates to photosensitive sensor groups comprising vertically stacked sensors. In each group, the semiconductor material filters normally incident electromagnetic radiation (or other materials also filter the radiation), and each sensor simultaneously detects a different waveband. The invention also relates to an array of such sensor groups, where each sensor group is positioned at a different pixel location. Background technique [0002] As used herein, the expressions "optical filter" and "color filter" are used interchangeably in a broad sense to mean a device that selectively transmits or transmits at least one band of electromagnetic radiation incident thereon. reflective element. For example, one type of filter is a dichroic mirror, which both transmits radiation in a first waveband and reflects radiation in a second waveband. Examples of optical filters include filters that pass short wavelengths, filters that pass long ...

AI Technical Summary

Problems solved by technology

Disadvantages of such sensors are: difficult and non-standard fabrication techniques; use of structures that do not allow for high sensor density (in an array); inability to select different colors for readout; and inability to use a single semiconductor substrate for three or more color detection

The performance of such sensor arrays is limited by the poor color response of the double-junction photodiode, and also by the fact that an n-type well forms the cathode of these two photodiodes, making the sensor design highly susceptible to color channel differences between the two photodiodes. Effects of nonlinear crosstalk

Additionally, the authors cite non-uniformity and processing / manufacturing limitations that limit the performance and potential benefits of this design

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