Semiconductor Termination Structure Leakage Current
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Solution Overview
Problem
The VLD structure in power semiconductor devices has low impurity concentration, leading to increased leakage current and depletion layer reaching electrodes during the OFF state, and increasing the number of manufacturing processes to address this issue is cumbersome.
Innovation Solution
A semiconductor device design with a semiconductor substrate having a first conductivity type, multiple regions of varying impurity concentrations, and insulating films with strategically placed electrodes to manage impurity distribution and reduce leakage current, including a p+ type semiconductor region with higher impurity concentration surrounding a p type region, and a field plate electrode connected to the p+ type region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a VLD structure with low impurity concentration is used, then the size of the termination structure is reduced, but the depletion layer reaches the electrode during OFF state and leakage current increases
Solution Approach 1:
The patent applies local quality by creating multiple regions with different impurity concentrations within the termination structure. Specifically, it introduces a first semiconductor region with first conductivity type impurity, a second semiconductor region with second conductivity type impurity surrounding the first region, and a third semiconductor region with higher second conductivity type impurity concentration surrounding the second region. This spatial variation in impurity concentration and conductivity type allows different parts of the termination structure to serve different functions: the low impurity concentration regions help reduce size while the higher impurity concentration regions prevent depletion layer penetration and reduce leakage current.
2Reliability
If a semiconductor layer with higher concentration is formed separately to prevent depletion layer reaching electrode, then leakage current is reduced, but the number of manufacturing processes increases
Solution Approach 1:
The patent merges multiple functions into a single integrated termination structure. Instead of forming separate semiconductor layers with different impurity concentrations as distinct manufacturing steps, the invention combines the termination structure with multiple doped regions (first, second, and third semiconductor regions) into one unified structure. This integration allows the device to achieve both size reduction and leakage current prevention through a single manufacturing process, thereby reducing overall device complexity while maintaining reliability.
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
This design enhances breakdown voltage by reducing current concentration and preventing local damage, ensuring uniform avalanche current flow and increased reliability of the semiconductor device.
Implementation Method 1
A first insulating film is provided on a part of the first surface at which the second semiconductor region is provided, the first insulating film having an opening that exposes. A first electrode is provided on the first insulating film and electrically connected to the third semiconductor region via the opening
Implementation Method 2
since the impurity concentration in the VLD structure is low, there is a problem in that the depletion layer reaches an electrode during an OFF state, and the leakage current increases
Implementation Method 3
This design enhances breakdown voltage by reducing current concentration and preventing local damage, ensuring uniform avalanche current flow and increased reliability of the semiconductor device
Data Source
AI summary
A semiconductor device includes a semiconductor substrate of a first conductivity type. The semiconductor substrate includes a first semiconductor region of a second conductivity type at a surface thereof, a second semiconductor region of the second conductivity type at the surface and surrounding the first semiconductor region, a third semiconductor region of the second conductivity type provided in the second semiconductor region at the surface and surrounding the first semiconductor region. The third semiconductor region has a concentration of a second conductivity type impurity higher than that of the second semiconductor region. A first insulating film is provided on a part of the first surface at which the second semiconductor region is provided. the first insulating film having an opening that exposes. A first electrode is provided on the first insulating film and electrically connected to the third semiconductor region via the opening.