LDMOS Compensation Doping Region Prevents Ion Diffusion
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Solution Overview
Problem
Conventional LDMOS devices face issues with reduced drive current due to excessive diffusion of doping ions into isolation structures, leading to high resistance regions and compromised electrical properties.
Innovation Solution
A semiconductor structure and fabrication method involving a compensation doping region formed in the substrate's trench side surface adjacent to the well region, which connects with the isolation structure and has the same doping type as the drift region, preventing excessive ion diffusion and maintaining ion concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doping ions are introduced into the drift region during fabrication, then the drift region achieves necessary conductivity for high voltage operation, but excessive diffusion of doping ions into the isolation structure occurs, creating high resistance regions that reduce drive current
Solution Approach 1:
A compensation doping region is introduced as an intermediary structure between the drift region and the isolation structure. This compensation region, formed with the same doping type as the drift region, acts as a buffer that prevents excessive diffusion of doping ions into the isolation structure, thereby maintaining proper ion concentration distribution and preventing high resistance region formation while preserving breakdown voltage characteristics
Solution Approach 2:
The compensation doping region is formed in advance before the drift region doping process. By pre-establishing this doping region adjacent to the isolation structure, the patent prevents excessive doping ion diffusion into the isolation structure during subsequent processing steps, thereby maintaining manufacturing precision in doping ion distribution while ensuring reliable high voltage operation
2Reliability
If the drift region is made longer to sustain higher potential, then breakdown voltage increases, but the device area increases and drive current decreases due to higher resistance
Solution Approach 1:
The patent applies local quality by creating a compensation doping region with specific doping characteristics in a localized area adjacent to the isolation structure, while maintaining the overall drift region structure. This localized doping enhancement improves charge distribution specifically where needed, reducing resistance in critical areas without requiring an overall reduction in drift region length, thereby maintaining breakdown voltage while improving drive current
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 approach enhances the drive current and electrical properties of LDMOS devices by preventing the formation of high resistance regions, thereby improving switching characteristics and breakdown voltage.
Implementation Method 1
excessive diffusion of doping ions into isolation structures
Data Source
AI summary
The present disclosure provides semiconductor structures. An exemplary semiconductor structure includes a substrate having a first region and a second region; an isolation structure formed in the substrate in the first region; a compensation doping region formed in the substrate in the first region, locate at a side of the isolation structure adjacent to the substrate in the second region and connecting with the isolation structure; a well region formed in the substrate in the second region; a drift region formed in the substrate in the first region and enclosing the isolation structure and the compensation doping region; a gate structure formed over the substrate in a boundary region between the first region and the second region; a source region formed in the well region at one side of the gate structure; and a drain region formed in the drift region at another side of the gate structure.