Semiconductor Structure with Graded Dielectric Layers
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Solution Overview
Problem
Traditional power semiconductor diodes experience premature breakdown and low breakdown voltage due to the concentration of electric field at the PN junction interface, limiting their performance in high-voltage applications.
Innovation Solution
A semiconductor structure with a PN junction surrounded by insulating material layers having different relative dielectric constants, which optimizes electric field distribution and reduces peak electric field intensity, thereby enhancing breakdown voltage without the need for field rings or metal field plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the doping concentration at the low doped side is reduced to increase breakdown voltage, then the breakdown voltage increases initially, but the base width increases and the maximum electric field intensity decreases, making it difficult to reach the critical breakdown electric field
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping concentration distribution within the low doped region. Specifically, the doping concentration is designed to be higher near the PN junction interface and gradually decrease towards the opposite end. This local variation allows the electric field to be sufficiently concentrated at the junction interface to achieve avalanche breakdown while maintaining an overall wider base width for higher breakdown voltage.
Solution Approach 2:
The patent changes the doping concentration parameter from a uniform distribution to a graded distribution. The doping concentration profile is specifically designed to vary spatially, with higher concentrations near the junction and lower concentrations further away. This parameter change enables simultaneous achievement of high electric field intensity at the junction and extended base width for higher breakdown voltage.
2Strength
If the length of the low doped region is increased to improve breakdown voltage, then the breakdown voltage increases, but the device area increases and further improvement becomes saturated
Solution Approach 1:
The patent uses local quality by concentrating the doping variation in the region near the PN junction interface. The high doping concentration is localized near the junction where the electric field is strongest, while the doping concentration decreases towards the opposite end. This allows achieving high breakdown voltage with a more compact device structure compared to uniform doping designs.
3Ease of manufacture
If the radius of curvature at the PN junction interface is reduced, then the manufacturing is easier, but the electric field becomes more concentrated and avalanche breakdown occurs earlier, reducing breakdown voltage
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping concentration that is higher near the PN junction interface. This local doping enhancement compensates for the electric field concentration effect caused by small radius of curvature. The higher doping concentration near the junction increases the critical breakdown electric field, allowing the device to maintain high breakdown voltage even with smaller junction curvature that is easier to manufacture.
Solution Approach 2:
The patent effectively creates a composite doping structure with different doping concentrations in different regions. The low doped region has a graded profile that transitions from higher concentration near the junction to lower concentration further away. This composite doping approach allows simultaneous achievement of manufacturable junction geometry and high breakdown voltage performance.
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
Significantly improves breakdown voltage and prevents premature breakdown, reducing chip area and costs while enhancing device reliability by uniformly distributing the electric field and reducing field concentration.
Implementation Method 1
a plurality of insulating material layers located outside the PN junction and distributed along the superposition direction of the P-type semiconductor material layer and the N-type semiconductor material layer, the relative dielectric constants of the adjacent insulating material layers are different
Data Source
AI summary
A semiconductor structure, a semiconductor assembly and a power semiconductor device. The semiconductor structure includes: a P-type semiconductor material layer; an N-type semiconductor material layer adjacent to the P-type semiconductor material layer, wherein the N-type semiconductor material layer and the P-type semiconductor material layer together from a PN junction; and a plurality of insulating material layers located outside the PN junction and distributed along the superposition direction of the P-type semiconductor material layer and the N-type semiconductor material layer, wherein the relative dielectric constants of the adjacent insulating material layers are different. The semiconductor structure in the present invention significantly optimizes the distribution of an electric field during the off-state high voltage operation of a device, greatly improves the breakdown voltage of the device, avoids the premature breakdown of the device caused by the concentration effect of the electric field at the edge of the junction.