Semiconductor Diode Potential Isolation Leakage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor devices with a diode structure, parasitic bipolar transistors form due to the p-type substrate and n-type epitaxial layer, leading to increased current leakage to the substrate when the diode operates, which affects the diode's withstand voltage and efficiency.
Innovation Solution
A semiconductor device with a potential isolation element that separates the diode from the substrate, comprising specific conduction type layers and regions, reduces current leakage by electrically isolating the diode and controlling the potential difference, thereby enhancing the diode's withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional diode structure with p-type substrate and n-type epitaxial layer is used, then the diode can be manufactured with standard processes, but a parasitic bipolar transistor is formed causing increased current leakage to the substrate
Solution Approach 1:
An n-type potential isolation layer is introduced as an intermediary between the p-type substrate and the diode structure. This isolation layer acts as a mediator that prevents the formation of the parasitic bipolar transistor by blocking the current path to the substrate, thereby reducing current leakage while maintaining standard manufacturing processes
Solution Approach 2:
The substrate structure is segmented into distinct functional layers: the original p-type substrate, the added n-type potential isolation layer, and the diode structure. This segmentation separates the current paths and prevents the parasitic transistor from forming, addressing the leakage issue without complicating manufacturing
2Reliability
If the diode operates with higher potential in the epitaxial substrate, then the diode can function properly, but the parasitic bipolar transistor starts to operate increasing leaked current
Solution Approach 1:
The n-type potential isolation layer serves as a mediator that allows the diode to operate at required potentials while preventing the parasitic bipolar transistor from activating. By blocking the current path to the p-type substrate, it eliminates energy loss through leakage current
Solution Approach 2:
The potential isolation layer converts the harmful effect of high potential operation (which activates the parasitic transistor) into a beneficial outcome by using the potential difference to create an effective barrier that blocks leakage current while maintaining necessary diode operation
Data Source
AI summary
A potential isolation element is provided separately from a diode. An n-type low-concentration region is formed on a P-type layer. A first high-concentration N-type region is positioned in the n-type low-concentration region and is connected to a cathode electrode of the diode. A second high-concentration N-type region is positioned in the n-type low-concentration region, is disposed to be spaced from a first second-conduction-type high-concentration region, and is connected to a power supply interconnection of a first circuit. A first P-type region is formed in the n-type low-concentration region, and a bottom portion thereof is connected to the P-type layer. A ground potential is applied to the first P-type region, and the first P-type region is positioned in the vicinity of the first high-concentration N-type region.