US 11621360

US Patent 11,621,360 Summary

Title: Microstructure enhanced absorption photosensitive devices

Assignee: W&w Sens Devices Inc.

Inventors: Shih-Yuan Wang, Shih-Ping Wang

Filing Date: March 29, 2022

Issue Date: April 4, 2023

Abstract:
A photodetector with microstructure-enhanced photoabsorption includes a cathode region, an anode region, reverse biasing circuitry, and a microstructure-enhanced photon absorbing semiconductor region. The absorbing region contains microstructures dimensioned and positioned to increase photon absorption across a range of wavelengths, including that of a source signal. These microstructures have at least one dimension equal to or shorter than the longest signal wavelength and can be pillars, holes, and/or voids, arranged periodically, non-periodically, randomly, or multi-periodically. They can increase absorption by forming an absorbing mode high contrast grating utilizing resonance, scattering, near-field, sub-wavelength, and/or interference effects. The absorbing region and microstructures can be made of silicon, germanium, or III-V materials. The invention also describes a photovoltaic device with buried voids in a semiconductor material to enhance solar radiation conversion efficiency, and a microwave transmission line structure with dielectric-filled voids to reduce the dielectric constant, dispersion, and loss. Additionally, an optical waveguide structure with microstructured voids to alter its effective refractive index, and a heat exchanger system with buried voids to control thermal conductivity and reduce thermal crosstalk are disclosed.

Plain-Language Overview of Independent Claims:

• Claim 1: This claim describes a photodetector that converts photons into electrons. It includes a cathode, an anode, and circuitry to apply a reverse voltage. The key feature is a semiconductor region designed to absorb photons, which contains a collection of very small structures (microstructures). These microstructures are specifically sized and placed to improve the absorption of light, particularly at certain wavelengths. At least one dimension of these microstructures is equal to or smaller than the longest wavelength of the light signal being detected. These microstructures can be columns (pillars), holes, or empty spaces (voids) and can be arranged in various patterns (periodic, non-periodic, random, or multi-periodic). The way they enhance absorption involves optical effects like resonance, scattering, near-field interactions, sub-wavelength phenomena, and interference.
• Claim 14: This claim outlines a photovoltaic device, which is designed to convert solar energy into electricity. It features a semiconductor material that has multiple empty spaces (voids) embedded within it. These buried voids are structured at a microscopic level to boost the semiconductor material's ability to absorb light, thereby making the device more efficient at converting solar radiation into direct current electricity.
• Claim 15: This claim describes a microwave transmission line system. It consists of a semiconductor substrate material that has numerous high-density voids filled with a dielectric material. The purpose of these voids is to lower the dielectric constant of the semiconductor, which in turn helps reduce signal loss and dispersion in the microwave transmission lines. At least one metallic microwave transmission line is positioned above this modified semiconductor substrate.
• Claim 16: This claim describes an optical waveguide structure, which is designed to guide light. It includes an "optical mode region" where the light travels and a "supporting semiconductor material" located next to this region. The supporting material incorporates a plurality of microstructured voids. These voids are specifically configured to change the effective refractive index of the supporting material, depending on their size, shape, and density.
• Claim 17: This claim describes a heat exchanger system. It comprises a device that generates heat and a heat sink that dissipates this heat into the surroundings. An intermediate material is placed between the heat-generating device and the heat sink. This intermediate material contains multiple buried voids which are designed to influence its thermal conductivity. Some of these voids can be filled with materials that conduct heat well, while others are filled with materials that isolate heat, arranged in a way that directs heat from the generating device to the heat sink while minimizing unwanted heat transfer (thermal cross-talk) to other sensitive devices.