Semiconductor Device With Deep Well Region For Carrier Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices, such as IGBTs, face challenges in maintaining low ON voltage and high withstand capability due to insufficient carrier extraction from the drift region during turn-off, leading to reduced performance.
Innovation Solution
The semiconductor device incorporates a first well region extending deeper than dummy trench portions, along with specific trench and mesa structures, to enhance carrier extraction efficiency and adjust switching speed, while also including accumulation regions and varying trench and mesa widths to optimize carrier accumulation and extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If carriers are accumulated in a drift region to lower ON voltage, then ON voltage is reduced, but carrier extraction becomes insufficient leading to reduced withstand capability
Solution Approach 1:
The drift region is segmented into multiple regions with different doping concentrations (first drift region with lower concentration and second drift region with higher concentration). This segmentation allows carriers to be accumulated in the first drift region to lower ON voltage, while the second drift region provides sufficient carrier extraction capability to maintain withstand capability during turn-off.
Solution Approach 2:
Different regions of the drift region are assigned different doping concentrations to perform different functions. The first drift region (lower doping concentration) is optimized for carrier accumulation to reduce ON voltage, while the second drift region (higher doping concentration) is optimized for carrier extraction to ensure withstand capability. This local quality differentiation resolves the contradiction between lowering ON voltage and maintaining reliability.
2Reliability
If carrier extraction is enhanced to improve withstand capability, then reliability is improved, but ON voltage increases
Solution Approach 1:
The drift region is divided into two segments with different doping concentrations. The first drift region maintains low doping concentration to enable carrier accumulation and keep ON voltage low, while the second drift region has higher doping concentration to provide sufficient carrier extraction capability for maintaining withstand capability.
Solution Approach 2:
The drift region employs local quality variation through different doping concentrations in different areas. The first drift region has lower doping concentration optimized for low ON voltage operation, while the second drift region has higher doping concentration optimized for carrier extraction and withstand capability. This local differentiation allows simultaneous optimization of both parameters.
3Productivity
If switching speed is increased to improve productivity, then turn-off time is reduced, but carrier extraction becomes insufficient leading to reduced reliability
Solution Approach 1:
The drift region is segmented into first and second drift regions with different doping concentrations. The second drift region with higher doping concentration provides enhanced carrier extraction capability that ensures sufficient carrier removal even during fast switching operations, thereby maintaining withstand capability while enabling high switching speed.
Solution Approach 2:
Different regions of the drift region have different doping concentrations to optimize for different functions. The second drift region's higher doping concentration locally enhances carrier extraction speed, enabling fast switching while maintaining reliability. This local quality optimization allows high productivity without sacrificing 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 configuration effectively lowers the ON voltage and maintains high withstand capability by improving carrier extraction speed and adjusting switching characteristics.
Implementation Method 1
accumulating carriers such as holes in a drift region
Implementation Method 2
extraction of carriers for example at the time of turn-off of a semiconductor device
Implementation Method 3
The semiconductor device may include a second conductivity type base region that is provided: in a region of the semiconductor substrate adjacent to any of the gate trench portions; and between the upper surface of the semiconductor substrate and the drift region
Data Source
AI summary
A semiconductor device is provided, including a semiconductor substrate; a first conductivity type drift region provided inside the semiconductor substrate; a plurality of gate trench portions provided extending from an upper surface of the semiconductor substrate and reaching the drift region; a dummy trench portion provided between two gate trench portions and provided extending from the upper surface of the semiconductor substrate and reaching the drift region; a second conductivity type base region provided: in a region of the semiconductor substrate adjacent to any of the gate trench portions; and between the upper surface of the semiconductor substrate and the drift region; and a second conductivity type first well region provided: in a region of the semiconductor substrate adjacent to the dummy trench portion; and reaching a position deeper than a lower end of the dummy trench portion; and having a doping concentration higher than that of the base region.