Trench Semiconductor Layout for Low On-Voltage Without Snapback
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Solution Overview
Problem
Conventional semiconductor devices with trench gate structures face challenges in optimizing the forward conduction characteristics and suppressing snapback phenomena, which affect the dynamic breakdown voltage and current flow efficiency.
Innovation Solution
The semiconductor device incorporates specific doping regions, such as the first and second lower end regions, with tailored doping concentrations and structures to relax electric field strengths and control current flow, including the use of first and second lower end regions with distinct doping profiles and mesa portion arrangements to manage trench portion interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the well region is positioned close to the cathode to reduce on-voltage, then forward conduction loss is reduced, but dynamic breakdown voltage decreases and reliability deteriorates
Solution Approach 1:
The device is divided into transistor portions and diode portions arranged in an alternating pattern. The well region is positioned only in the transistor portions, while the diode portions have a different structure without the well region. This segmentation allows the on-voltage to be reduced in transistor regions while maintaining dynamic breakdown voltage in diode regions, resolving the contradiction between low on-voltage and high breakdown voltage.
Solution Approach 2:
Different regions of the semiconductor device are given different structures and doping concentrations tailored to their specific functions. The transistor portions have a well region with high doping concentration optimized for low on-voltage, while the diode portions have a structure optimized for high dynamic breakdown voltage. This local differentiation allows each region to perform optimally without compromising the other.
2Productivity
If alternating transistor and diode portions are arranged to optimize carrier injection, then switching performance is improved, but device structure becomes more complex
Solution Approach 1:
The semiconductor device is segmented into alternating transistor portions and diode portions along the first direction. Each transistor portion contains a well region and is configured for high-speed switching with optimized carrier injection, while each diode portion is configured for reverse conduction. This segmentation enables optimized carrier injection in transistor regions while maintaining a relatively simple overall structure through regular alternating arrangement.
Data Source
AI summary
Provided is a semiconductor device including: a plurality of trench portions which are provided to positions below a base region from an upper surface of a semiconductor substrate and are arranged next to one another in a first direction on the upper surface of the semiconductor substrate; a first lower end region of a second conductivity type, which is arranged at a first depth position and is provided in contact with a lower end of two or more of the trench portions; and a second lower end region which is arranged at the first depth position and is arranged at a position not overlapping with the first lower end region, in which the second lower end region includes at least one of a region of a first conductivity type or a region of a second conductivity type which has a lower doping concentration than the first lower end region.