Backside-Illuminated Lateral PIN Diode for Low-Energy Electron Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inspection systems, such as optical microscopes and typical detectors, struggle to achieve high-resolution imaging of sub-100 nanometer IC components due to limitations in resolution and inefficiencies in detecting low-energy particles, particularly electrons, leading to low responsivity and response speed.
Innovation Solution
A detector system with a silicon substrate thinner than 30 μm, featuring a lateral PIN diode on the front side and a uniform back side, configured for back-side illumination, which enhances detection response speed and responsivity by allowing electrons to pass through the substrate to a depletion region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional optical microscope is used for inspection, then the system is simple and easy to operate, but the resolution is limited to a few hundred nanometers due to the wavelength of light
Solution Approach 1:
The patent inverts the conventional detection approach by using back-side illumination instead of front-side illumination. The uniform back side of the silicon substrate serves as the illumination surface, allowing electrons to enter directly and reach the depletion region without passing through complex front-side structures, thereby achieving higher resolution while maintaining relative simplicity
Solution Approach 2:
The patent transitions from conventional front-side detection to back-side detection, effectively utilizing the third dimension (depth/thickness) of the silicon substrate. By thinning the substrate to 30 μm or less and creating a uniform back side, electrons can traverse the substrate thickness dimension to reach the depletion region, enabling higher resolution imaging
2Productivity
If the silicon substrate is thinned to 30 μm or less to improve electron detection, then the detection response speed and responsivity improve, but the substrate becomes more fragile and difficult to manufacture
Solution Approach 1:
The patent applies parameter changes by precisely controlling the silicon substrate thickness to 30 μm or less, and by controlling the dopant concentration in the intrinsic region to 1×10^12 to 1×10^14 atoms/cm³. These parameter optimizations enable high detection performance while maintaining manufacturability through standardized semiconductor processing techniques
Solution Approach 2:
The patent creates local quality differences by forming a depletion region with specific electrical properties in the intrinsic region between the p-type and n-type regions, while maintaining a uniform back side surface. This localized optimization of electrical properties enables high detection performance without compromising the overall substrate integrity
3Reliability
If a lateral PIN diode structure is used with back-side illumination, then carrier losses are reduced and responsivity increases, but the device structure becomes more complex
Solution Approach 1:
The patent extracts the detection function from the conventional front-side structure and relocates it to the back side of the substrate. By removing the need for complex front-side illumination paths and using a simple lateral PIN diode structure, the design achieves high responsivity with reduced carrier losses while maintaining relatively simple device architecture
Solution Approach 2:
The patent optimizes the doping concentration in the intrinsic region to 1×10^12 to 1×10^14 atoms/cm³, which is significantly lower than conventional designs. This parameter change reduces carrier losses and increases responsivity while maintaining a simple lateral PIN diode structure without requiring additional complex components
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 system improves detection efficiency and speed by increasing responsivity and reducing carrier losses, facilitating higher-resolution imaging of IC components with reduced parasitic capacitance and easy integration with readout circuits.
Implementation Method 1
a region between the p-type implant and the n-type implant configured to form a depletion region when a reverse bias is applied between the p-type implant and the n-type implant
Implementation Method 2
the lateral PIN diode is configured to detect an electron that enters the back side of the silicon substrate and passes through the silicon substrate to the depletion region
Data Source
AI summary
Systems, apparatuses, and methods include a detector including a detection element including a portion of a silicon substrate comprising: a front side of the portion of the silicon substrate including a PIN diode that comprises a p-type region and an n-type region; a back side of the portion of the silicon substrate, opposite of the front side, comprising a substantially uniform surface; and a layer on the back side of the portion of the silicon substrate; wherein: a region between the p-type region and the n-type region is configured to form a depletion region when a reverse bias is applied between the p-type region and the n-type region, and the PIN diode is configured to detect an electron that enters the back side of the portion of the silicon substrate and passes through the portion of the silicon substrate to the depletion region.