SiC Lateral PN Junction EUV Detector With Wider Active Absorption
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Solution Overview
Problem
Existing EUV detectors face low detection efficiency and stability due to strong absorption of EUV photons by non-active surface regions and high-energy photon irradiation, leading to noise and performance degradation, especially in harsh environments.
Innovation Solution
A novel SiC-based lateral PN junction EUV detector using selective-area ion implantation forms a lateral PN junction with a widened depletion region, allowing direct EUV photon absorption and improved carrier collection, reducing absorption by non-active surface regions and enhancing irradiation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a traditional structure PN junction detector or Schottky junction detector is used, then the device can be fabricated with conventional processes, but the detection efficiency is very low due to strong absorption of EUV photons by non-active surface regions
Solution Approach 1:
The patent transitions from a conventional vertical detector structure to a lateral PN junction structure. The depletion region is extended laterally rather than vertically, allowing EUV photons to enter the active region directly without passing through thick surface layers. This dimensional change in the junction architecture enables efficient EUV detection while maintaining fabrication feasibility through selective ion implantation.
Solution Approach 2:
The patent applies selective-area ion implantation to create localized P-type or N-type well regions within the lightly-doped epitaxial layer. This creates a lateral PN junction with a depletion region confined to specific areas, optimizing the active detection region while minimizing absorption in non-active surface regions. The local modification of doping profiles enables precise control over the depletion region geometry.
2Reliability
If existing SiC-based ultraviolet detectors are used, then the material provides visible blindness and high thermal conductivity, but the detectors suffer from strong absorption of EUV photons by non-active surface regions resulting in very low detection efficiency
Solution Approach 1:
The patent extends the depletion region laterally through selective ion implantation rather than relying on vertical junction depth. This lateral extension allows EUV photons to be absorbed in the active region without requiring thinning of surface layers, directly addressing the absorption problem while maintaining the beneficial properties of SiC material.
Solution Approach 2:
The patent modifies the doping concentration parameters by creating lightly-doped epitaxial layers with specific doping levels (e.g., 1×10^16 to 1×10^18 atoms/cm³) and then applying selective ion implantation to create higher doping regions. This parameter optimization ensures the depletion region extends sufficiently laterally to capture EUV photons while minimizing absorption in non-active regions.
3Reliability
If Schottky junction detectors are used, then the device structure is simple, but positive vacancies are generated under high-energy EUV photon irradiation resulting in reduced Schottky barrier height and increased leak current
Solution Approach 1:
The patent replaces the Schottky junction structure, which is prone to vacancy-related degradation under EUV irradiation, with a PN junction structure. The PN junction's depletion region, formed by selective ion implantation, is inherently more resistant to radiation-induced vacancy effects. This structural conversion eliminates the harmful vacancy generation mechanism while maintaining detector functionality.
Solution Approach 2:
The patent uses a composite doping structure within the SiC epitaxial layer, combining lightly-doped regions with selectively implanted higher-doping regions. This composite doping profile creates a lateral PN junction that leverages the radiation hardness of SiC while mitigating the specific vulnerability of Schottky junctions to vacancy generation through architectural modification.
4Manufacturing precision
If the depletion region is extended to improve carrier collection, then the detection efficiency increases, but the device becomes more sensitive to high-energy photon irradiation effects
Solution Approach 1:
The patent creates localized high-doping regions through selective ion implantation, forming a lateral PN junction with a confined depletion region. This local quality modification ensures the depletion region is precisely positioned and sized to optimize carrier collection from the active region while limiting exposure to harmful high-energy photon effects to only the necessary active volume.
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 significantly improves detection efficiency and stability, maintaining low noise levels and radiation resistance, even under extreme temperatures, facilitating reliable long-term operation in EUV environments.
Implementation Method 1
The EUV detection technology is mainly used to detect short-wavelength and high-energy ultraviolet light with a wavelength ranging from 10 nm to 200 nm
Implementation Method 2
a lateral PN junction with a widened depletion region, allowing direct EUV photon absorption and improved carrier collection
Implementation Method 3
selective-area ion implantation forms a lateral PN junction with a widened depletion region
Data Source
AI summary
The present invention discloses a novel silicon carbide-based lateral PN junction extreme ultraviolet detector with enhanced detection performance based on selective-area ion implantation, including an N-type ohmic contact lower electrode, an N-type substrate and a lightly-doped epitaxial layer which are connected sequentially from bottom to top, where the lightly-doped epitaxial layer is an N-type lightly-doped epitaxial layer or a P-type lightly-doped epitaxial layer; in a case that the lightly-doped epitaxial layer is an N-type or P-type lightly-doped epitaxial layer, a P-type or N-type well region is formed on the surface of the N-type or P-type lightly-doped epitaxial layer through the selective-area ion implantation, a P-type or N-type ohmic contact upper electrode is arranged on the P-type or N-type well region, and the P-type or N-type ohmic contact upper electrode is provided with a metal conductive electrode along its periphery.