Semiconductor Accumulation Region Doping Profile for Low ON Voltage
Solution Overview
Problem
Current semiconductor devices face challenges in optimizing the doping concentration distribution within accumulation regions and trench bottom portions to enhance carrier injection effects while maintaining breakdown voltage and reducing ON voltage.
Innovation Solution
The semiconductor device incorporates an accumulation region with a doping concentration profile formed by implanting ions from the side walls of trench portions into the mesa portions at an inclined angle, and a trench bottom portion with a specific doping concentration to improve carrier injection and reduce electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doping concentration in the accumulation region is increased to enhance carrier injection effect, then the ON voltage is reduced, but the breakdown voltage decreases
Solution Approach 1:
The patent applies local quality by creating distinct doping concentration zones within the accumulation region. Specifically, it forms a first accumulation region with a first doping concentration and a second accumulation region with a second doping concentration that is higher than the first. This spatial differentiation allows the first accumulation region to contribute to breakdown voltage while the second accumulation region enhances carrier injection and reduces ON voltage.
Solution Approach 2:
The patent segments the accumulation region into multiple sub-regions with different doping concentrations. The accumulation region is divided into a first accumulation region (with lower doping concentration) and a second accumulation region (with higher doping concentration). This segmentation enables each sub-region to fulfill different functional requirements: the first sub-region maintains electrical strength for breakdown voltage, while the second sub-region provides strong carrier injection for low ON voltage.
2Manufacturing precision
If ions are implanted from the side walls of trench portions at an inclined angle to optimize doping distribution, then manufacturing complexity increases, but doping precision and carrier injection effect are improved
Solution Approach 1:
The patent transitions from conventional vertical ion implantation to inclined-angle ion implantation from the side walls of trench portions. This dimensional change in the implantation approach allows ions to reach specific depth profiles and spatial distributions that are not achievable with perpendicular implantation alone, thereby optimizing the doping concentration distribution in the accumulation regions.
Solution Approach 2:
The patent performs preliminary actions by forming the trench portions and determining their orientations before conducting the ion implantation. The trench portions are specifically configured with certain orientations to enable subsequent inclined-angle ion implantation from their side walls. This preliminary structuring facilitates the precise doping distribution achieved in the accumulation regions.
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 configuration enhances the carrier injection effect, lowers ON voltage, and maintains or improves breakdown voltage by optimizing the doping concentration distribution within the accumulation and trench bottom regions.
Implementation Method 1
a doping concentration distribution in which an accumulation region 16 having a doping concentration higher than that of a drift region 18 is provided in a mesa portion 28 between adjacent gate trench portions 40
Data Source
AI summary
Provided is a semiconductor device including a transistor portion, in which the transistor portion has a drift region of a first conductivity type provided in a semiconductor substrate, a base region of a second conductivity type provided above the drift region, an accumulation region of the first conductivity type provided above the drift region, a plurality of trench portions provided to extend from a front surface of the semiconductor substrate to the drift region, and a trench bottom portion of the second conductivity type provided in bottom portions of the plurality of trench portions, and the accumulation region has a doping concentration with a half width of 0.3 μm or more.