Semiconductor Device Lifetime Control Layer Proton Irradiation Depth
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Solution Overview
Problem
Existing methods for evaluating carrier lifetime in semiconductor devices are inefficient, as they require time-consuming simulations and are unsuitable for mass production, making it difficult to achieve accurate and prompt feedback, especially when controlling the depth of proton irradiation.
Innovation Solution
A semiconductor device with a lifetime control layer and a crystal defect layer, where the depth is determined by measuring resistance or current values using measurement electrodes, allowing for precise control and immediate feedback through proton irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If simulation method is used to obtain lifetime value, then evaluation can be performed, but time consumption increases and productivity decreases
Solution Approach 1:
The patent creates a copy of the measurement approach by forming a measurement layer that replicates the electrical characteristics of the drift layer. This allows direct measurement of lifetime characteristics without requiring time-consuming simulations, as the measurement layer serves as a surrogate that provides immediate feedback on lifetime values.
Solution Approach 2:
The measurement layer acts as an intermediary between the proton irradiation process and the lifetime evaluation. By placing measurement electrodes on this intermediate layer, the system can directly measure lifetime characteristics rather than requiring simulation to translate process parameters into lifetime values.
2Measurement precision
If TEG is used for lifetime evaluation, then characteristics can be measured, but product characteristics are affected and depth control becomes difficult
Solution Approach 1:
The patent segments the semiconductor structure into distinct functional regions: an effective region for principle current flow and an ineffective region containing the measurement layer. This segmentation allows the measurement layer to be irradiated independently to create a crystal defect layer for depth reference, while the drift layer receives controlled irradiation for lifetime modification without the two processes interfering with each other.
Solution Approach 2:
The crystal defect layer formed in the measurement layer serves as an intermediary reference marker. By measuring the depth of this crystal defect layer, the system can determine the proton irradiation depth without the measurement process itself affecting the product characteristics or requiring complex depth control during the actual lifetime-modifying irradiation.
3Productivity
If integral measurement of multiple production parameters is used, then evaluation can be performed, but evaluation accuracy deteriorates
Solution Approach 1:
The measurement layer creates a direct electrical copy of the drift layer's carrier transport properties. By measuring electrical characteristics (such as carrier lifetime, mobility, or resistance) directly through electrodes on the measurement layer, the system obtains accurate lifetime evaluation without needing to integrally measure multiple production parameters and combine them through complex relationships.
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
Enables easy determination of the depth of the lifetime control layer, improving evaluation accuracy and allowing for prompt feedback and control of proton irradiation depth, facilitating in-process screening and feedback.
Implementation Method 1
the measurement layer measures characteristics related to a lifetime of a carrier
Implementation Method 2
performing proton irradiation from above the mask, thereby forming a lifetime control layer in the effective region
Implementation Method 3
measuring a resistance value between the plurality of measurement electrodes
Data Source
AI summary
A semiconductor device according to the present disclosure includes a semiconductor substrate having an effective region and an ineffective region, an upper surface electrode layer provided on an upper surface of the semiconductor substrate and a rear surface electrode layer provided on a rear surface of the semiconductor substrate, wherein the semiconductor substrate includes a lifetime control layer that is provided in the effective region, a measurement layer provided at an upper surface side of the ineffective region and a crystal defect layer that is provided in the ineffective region, the upper surface electrode layer includes a plurality of measurement electrodes provided on the measurement layer, the measurement layer includes a conducting layer at least at a portion where the plurality of measurement electrodes are provided, and the crystal defect layer is provided between the plurality of measurement electrodes.