US 2022/0190010 A1 · OPTIMAL PHOTON MANAGEMENT FOR CMOS SENSORS

Abstract

A CMOS sensor includes a silicon material having a surface periodic structure of silicon portions and non-silicon portions, formed by multiple supercells repeated in a 2-dimensional lattice pattern. Each image pixel of the sensor has at least 2×2 supercells. The lattice constants in both lateral directions are within a range defined by a wavelength of the light to be sensed. Within each supercell, the non-silicon portions create an effective refractive index for the light that changes gradually with depth. The non-silicon portions within the supercell have lateral feature sizes smaller the wavelength of the light to be sensed, and vertical feature sizes larger than the wavelength of the light to be sensed. In some examples, each supercell includes at least two inverted pyramids having different base sizes and/or different heights. A dielectric material fills the non-silicon portions of the periodic structure and covers the silicon material.

Claims20

Dependent claims

An energy absorber for absorbing an electromagnetic wave, comprising:

a semiconductor material having a periodic structure formed in a surface layer, the periodic structure including semiconductor portions and non-semiconductor portions,
wherein the periodic structure includes a plurality of supercells repeated according to a 2-dimensional lattice pattern, the supercell being a smallest unit of the periodic structure,
wherein lattice constants of the 2-dimensional lattice pattern in both lateral directions are within a range defined by a wavelength of the electromagnetic wave to be absorbed,
wherein within each supercell, a total area of the non-semiconductor portions at a given depth from a top of the periodic structure is a monotonically or near-monotonically decreasing function of the depth, wherein lateral feature sizes of the non-semiconductor portions within the supercell are smaller than a lower end of a wavelength range of the electromagnetic wave to be absorbed, and wherein vertical feature sizes of the non-semiconductor portions within the supercell are larger than an upper end of the wavelength range of the electromagnetic wave to be absorbed;
and
a dielectric material filling the non-semiconductor portions of the periodic structure and covering the semiconductor material.

3 more elements

A CMOS (Complementary Metal Oxide Semiconductor) image sensor for sensing an electromagnetic wave, comprising:

a silicon material defining a plurality of image pixels, each pixel having a periodic structure formed in a surface layer, the periodic structure including silicon portions and non-silicon portions,
wherein the periodic structure includes a plurality of supercells repeated according to a 2-dimensional lattice pattern, including at least two supercells in each of two lateral directions of the lattice pattern, the supercell being a smallest unit of the periodic structure,
wherein lattice constants of the 2-dimensional lattice pattern in both lateral directions are within a range defined by a wavelength of the electromagnetic wave to be sensed,
wherein within each supercell, a total area of the non-silicon portions at a given depth from a top of the periodic structure is a monotonically or near-monotonically decreasing function of the depth, wherein lateral feature sizes of the non-silicon portions within the supercell are smaller than a lower end of a wavelength range of the electromagnetic wave to be sensed, and wherein vertical feature sizes of the non-silicon portions within the supercell are larger than an upper end of the wavelength range of the electromagnetic wave to be sensed;
and
a dielectric material filling the non-silicon portions of the periodic structure and covering the silicon material.

3 more elements

Dependencies are inferred from the claim text.

Optimal photon management for cmos sensors

Life of this patent

Optimal photon management for cmos sensors

Life of this patent

Abstract

Claims20