Current-Sensing Semiconductor Structure for Reverse-Bias Breakdown Control
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Solution Overview
Problem
Conventional semiconductor devices with current detection functions face issues where the current detection device is damaged before the main device due to lower withstand voltage, leading to unreliable monitoring of current flowing through the main device, especially under reverse bias and surge voltage conditions.
Innovation Solution
The semiconductor device design includes a current detection device with a higher withstand voltage than the main device, achieved by optimizing structural parameters such as diffusion depth, trench depth, and impurity density, and connecting a resistor between the main device and current detection device to ensure stable operation and prevent damage during reverse bias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the current detection device is designed with the same structural parameters as the main device, then the manufacturing process is simplified, but the current detection device has lower withstand voltage and is damaged before the main device under reverse bias
Solution Approach 1:
The patent applies local quality by giving the current detection device different structural parameters from the main device. Specifically, the diffusion depth of the body region in the current detection device is made shallower than in the main device, and the trench depth is made greater. These localized structural modifications increase the withstand voltage of the current detection device while keeping the manufacturing process relatively simple by using the same basic fabrication steps.
Solution Approach 2:
The patent changes key structural parameters of the current detection device to achieve higher withstand voltage. The diffusion depth of the body region is reduced, and the trench depth is increased compared to the main device. These parameter changes are implemented through controlled diffusion processes and trench etching, allowing the current detection device to withstand higher reverse bias voltages without being damaged first.
2Reliability
If the current detection device is designed with higher withstand voltage through optimized structural parameters, then reliability under reverse bias is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by giving the current detection device different structural parameters from the main device. Specifically, the diffusion depth of the body region in the current detection device is made shallower than in the main device, and the trench depth is made greater. These localized structural modifications increase the withstand voltage of the current detection device while keeping the manufacturing process relatively simple by using the same basic fabrication steps.
Solution Approach 2:
The patent changes key structural parameters of the current detection device to achieve higher withstand voltage. The diffusion depth of the body region is reduced, and the trench depth is increased compared to the main device. These parameter changes are implemented through controlled diffusion processes and trench etching, allowing the current detection device to withstand higher reverse bias voltages without being damaged first.
3Device complexity
If the current detection device shares the same gate and drain terminals with the main device, then the device structure is simplified, but the current detection becomes unreliable when the detection device is damaged first
Solution Approach 1:
The patent applies local quality by giving the current detection device different structural parameters from the main device. Specifically, the diffusion depth of the body region in the current detection device is made shallower than in the main device, and the trench depth is made greater. These localized structural modifications increase the withstand voltage of the current detection device while keeping the manufacturing process relatively simple by using the same basic fabrication steps.
Solution Approach 2:
The patent changes key structural parameters of the current detection device to achieve higher withstand voltage. The diffusion depth of the body region is reduced, and the trench depth is increased compared to the main device. These parameter changes are implemented through controlled diffusion processes and trench etching, allowing the current detection device to withstand higher reverse bias voltages without being damaged first.
Data Source
AI summary
Between a source electrode (25) of a main device (24) and a current sensing electrode (22) of a current detection device (21), a resistor for detecting current is connected. Dielectric withstand voltage of gate insulator (36) is larger than a product of the resistor and maximal current flowing through the current detection device (21) with reverse bias. A diffusion length of a p-body region (32) of the main device (24) is shorter than that of a p-body (31) of the current detection device (21). A curvature radius at an end portion of the p-body region (32) of the main device (24) is smaller than that of the p-body (31) of the current detection device (21). As a result, at the inverse bias, electric field at the end portion of the p-body region (32) of the main device (24) becomes stronger than that of the p-body region (31) of the current detection device (21). Consequently, avalanche breakdown tends to occur earlier in the main device 24 than the current detection device (21).