Massachusetts Institute of Technology

Kevin Ryu

Christopher W Leitz

Renee D Lambert

Donna-Ruth Webb Yost

Steven W Rabe

Vladimir Bolkhovsky

Brian F Aull

James A Gregory

Daniel R Schuette

David Volfson

Vyshnavi Suntharalingam

Joseph S Ciampi

Karl Alexander McIntosh

Marshall W Bautz

Peter W O'Brien

A chip-to-chip integration process for rapid prototyping of silicon avalanche photodiode (APD) arrays has been developed. This process has several advantages over wafer-level 3D integration, including: (1) reduced cost per development cycle since a dedicated full-wafer read-out integrated circuit (ROIC) fabrication is not needed, (2) compatibility with ROICs made in previous fabrication runs, and (3) accelerated schedule. The process provides several advantages over previous processes for chip-to-chip integration, including: (1) shorter processing time as the chips can be diced, bump-bonded, and then thinned at the chip-level faster than in a wafer-level back-illumination process, and (2) the CMOS substrate provides mechanical support for the APD device, allowing integration of fast microlenses directly on the APD back surface. This approach yields APDs with low dark count rates (DCRs) and higher radiation tolerance for harsh environments and can be extended to large arrays of APDs.

Rapid prototyping of single-photon-sensitive silicon avalanche photodiodes

A new process that enables void-free direct-bonded MBE-passivated large-format image sensors is disclosed. This process can be used to produce thin large-area image sensors for UV and soft x-ray imaging. Such devices may be valuable in future astronomy missions or in the radiology field. Importantly, by controlling the hydrogen concentration in the silicon oxide layers of the image sensor and the support wafer, voids in the bonding interface can be significantly reduced or eliminated. This process can be applied to any wafer that includes active circuitry and requires a second wafer, such as a support wafer.

Semiconductor surface passivation

An x-ray imaging device can include an x-ray detector and an optical-blocking filter. The x-ray detector has an entrance-window surface for receiving x-rays, at least one side surface, and a back surface facing in an opposite direction from the entrance-window surface. The optical-blocking filter is deposited on and fully covers at least the entrance-window surface and the side surface of the x-ray detector, wherein the optical-blocking filter blocks visible, ultraviolet, and near-infrared light.

Integrated optical blocking filter for compact X-ray imaging detector

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Arlington, MA, United States of America

Kevin Ryu