Backside-Illuminated Photon-Counting Sensor with MOS Detector
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Solution Overview
Problem
Current UV and IR detectors face challenges in achieving single-photon sensitivity and solar/visible-blind functionality, leading to inefficiencies in applications such as UV astronomy and IR spectroscopy due to high background noise from solar and visible light.
Innovation Solution
A semiconductor-based photon-counting sensor using a metal-oxide-semiconductor (MOS) structure with a pump-gate jot device, where the MOS detector is formed on the backside of a semiconductor substrate and the jot on the frontside, enabling monolithic integration and deep sub-electron read noise, allowing for solar/visible-blind UV detection and extended IR detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional UV detectors are used, then UV detection capability is provided, but background noise from solar and visible light increases detection difficulty
Solution Approach 1:
The detector is segmented into distinct functional layers: a MOS structure for UV photon absorption and carrier generation, and a separate jot device for signal amplification and readout. This segmentation allows the MOS layer to be optimized for solar-blind UV detection while the jot provides low-noise readout, resolving the contradiction between background noise rejection and single-photon sensitivity.
Solution Approach 2:
The patent introduces an insulating oxide layer as an intermediary between the metal electrode and semiconductor substrate. This oxide layer acts as a filter that blocks visible and solar light while allowing UV photons to generate carriers that can tunnel through the oxide, thereby eliminating background noise while preserving single-photon detection capability.
2Reliability
If hybrid configuration with separate substrates is used, then MOS UV detector and jot device can be independently optimized, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the MOS UV detector and the jot device into a single monolithic semiconductor structure. The MOS structure is formed directly on the semiconductor substrate that also contains the jot device, eliminating the need for hybrid stacking and bump-bonding processes. This integration maintains the independent optimization benefits while significantly reducing device complexity and manufacturing difficulty.
3Measurement precision
If standard readout mechanisms are used, then simple device structure is maintained, but read noise level increases and single-photon sensitivity is lost
Solution Approach 1:
The jot device employs dynamic voltage control through pump gates that can be switched between different potential states. By dynamically adjusting the gate voltages, the device can transfer accumulated charge packets to readout nodes with high precision, enabling single-photon detection while managing the inherent complexity through controlled dynamic operation.
Solution Approach 2:
The pump-gate jot device utilizes periodic voltage cycling to accumulate and transfer charge packets from the MOS detector. This periodic action allows the system to integrate multiple UV photon events over time while maintaining low read noise, achieving single-photon sensitivity through time-averaged signal accumulation rather than requiring complex instantaneous measurement circuits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves high sensitivity for single-photon detection and reduces background noise, enhancing the performance of UV and IR detectors by enabling solar/visible-blind functionality and extending the working wavelength of current Si-based IR detectors.
Implementation Method 1
a metal-insulator-semiconductor internal photoemission (e.g., thermionic-emission) detector formed on and/or in a first surface of a semiconductor substrate
Implementation Method 2
The insulating property of oxide layer helps reduce or eliminate dark current and other noises (signals from longer wavelengths)
Data Source
AI summary
Some embodiments of the present disclosure provide a semiconductor-based photon-counting sensor comprising a metal-insulator-semiconductor internal photoemission (e.g., thermionic-emission) detector formed on and/or in a first surface of a semiconductor substrate, and at least one jot formed on and/or in a second side of a semiconductor substrate. The at least one MIS photoemission detector and the at least one jot are configured such that a photocarrier generated in response to a photon incident on the MIS thermionic-emission detector is readout by the at least one jot.