US 9525084

US Patent 9,525,084, titled "Microstructure enhanced absorption photosensitive devices," was issued to W&wsens Devices Inc. on December 20, 2016. The application was filed on November 18, 2015, with inventors Shih-Yuan Wang and Shih-Ping Wang.

Abstract:
The patent describes microstructure-enhanced absorption photosensitive devices, such as photodiodes (PDs) and avalanche photodiodes (APDs). These devices incorporate microstructures, like holes, to significantly increase photon absorption. For silicon PDs and APDs, this design allows for bandwidths exceeding 10 Gb/s at 850 nm wavelengths, with quantum efficiencies of 90% or more. The thinness of these devices makes them suitable for integration with CMOS, BiCMOS, and other electronics on a single silicon chip, offering benefits in packaging, reduced capacitance, and higher operating speeds.

Plain-Language Overview of Independent Claims:

• Independent Claim 1: This claim describes an integrated detector/processor circuit for data communication on a single semiconductor chip. It includes a photodetector with a photon absorbing region containing multiple holes that concurrently receive the same optical source signal, converting it into an electrical signal. An electronic processor, also on the same chip, processes this electrical signal. Crucially, the photodetector's photon absorbing region and the electronic processor have thicknesses of the same order of magnitude. The device also includes cathode and anode regions.
• Independent Claim 13: This claim describes a photodetector itself, featuring microstructure-enhanced photoabsorption. It has a photon absorbing region (preferably 0.5 to 5 micrometers thick) that absorbs photons from a modulated source signal for data communication, producing an electrical output. This region contains a plurality of holes extending through at least part of its thickness, configured to concurrently receive the same source signal at multiple holes. The region is designed to absorb over 40% (or 50% or 60%) of the incident signal at wavelengths in the 800-900 nm range or 1400-1700 nm range.
• Independent Claim 25: This claim specifies a photodetector with microstructure-enhanced photoabsorption that is made of silicon. It includes a cathode region, an anode region, and reverse biasing circuitry. The silicon photon absorbing region contains multiple holes, each with a cross-section parallel to the upper substrate surface, having a maximum dimension between 400 nm and 2500 nm. The center of each hole is spaced less than 3500 nm from the center of its nearest adjacent hole.
• Independent Claim 35: This claim describes a photodetector with microstructure-enhanced photoabsorption, similar to Claim 25, but the photon absorbing region is made of a germanium-based material. The holes in this germanium-based region have a maximum dimension between 750 nm and 3000 nm, and their centers are spaced apart by less than 5000 nm from the center of a nearest adjacent hole.
• Independent Claim 39: This claim describes an optical/electronic system. It comprises a photodetector and an active electronic circuit built on the same semiconductor substrate, forming a single integrated circuit chip. The system also includes a laser modulated at Gb/s rates to generate an optical source signal and an optical fiber to transport this signal. The photodetector receives the signal from the fiber and converts it to an electrical output, which the active electronic circuit then processes and outputs.

Litigation Status:
The patent family for US9525084 has litigation associated with it. Specifically, a PTAB case IPR2025-00997 was filed (with a procedural termination), and a US case was filed in the Texas Eastern District Court (case 2:24-cv-00854). The first worldwide family litigation was also filed. There is no information in the CAFC 2026 dockets directly listing US9525084 as a scheduled case for oral argument or decision. The USPTO PatentCenter and Assignment Search provide general search functionality but do not list specific litigation for this patent in the immediate search results. The patent was reassigned to IP LITFIN US 2024 LLC on October 23, 2024, via a patent security agreement.