Semiconductor Trench Separation and Floating Region Design
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Solution Overview
Problem
Existing semiconductor devices face challenges in improving electrical characteristics, particularly in reducing reverse current and enhancing breakdown voltage, due to limitations in trench separation structures and floating regions.
Innovation Solution
A semiconductor device with a trench separation structure and a floating region is designed, where the trench separation structure demarcates an outer region and an active region, and the floating region is electrically connected to maintain an electrically floating state, forming a Schottky junction with the main surface in the active region to relax electric field intensity and prevent pn-junction formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trench separation structure is used to demarcate outer region and active region, then device structure is improved and electrical characteristics are enhanced, but manufacturing complexity increases
Solution Approach 1:
The semiconductor device is divided into distinct regions using trench separation structures. The trench extends from the surface into the semiconductor layer, creating separate outer regions and active regions. This segmentation allows independent optimization of each region's electrical characteristics while maintaining clear spatial demarcation, resolving the contradiction between improved electrical performance and structural complexity.
Solution Approach 2:
Different regions of the semiconductor device are given different properties through the trench separation structure. The outer region can have different doping concentrations and electrical characteristics compared to the active region. This local differentiation enables tailored electrical performance in specific areas without compromising the overall device structure, addressing the balance between electrical characteristics and manufacturing complexity.
2Reliability
If a floating region is formed in electrically floating state along the trench separation structure, then reverse current is suppressed and breakdown voltage is improved, but device structure becomes more complex
Solution Approach 1:
The floating region acts as an intermediary element between the trench separation structure and the Schottky electrode. It is positioned in the outer region adjacent to the trench, electrically isolated from both the anode and cathode. This intermediary structure helps distribute and relax the electric field intensity, preventing premature breakdown while suppressing reverse current, thus improving reliability without excessive structural complexity.
Solution Approach 2:
The floating region is maintained in an electrically floating state, creating an equipotential zone that helps equalize electric field distribution. By being electrically isolated and positioned strategically along the trench separation structure, it provides a neutral potential reference that relaxes electric field intensity peaks, thereby improving breakdown voltage characteristics.
3Reliability
If Schottky electrode forms Schottky junction with main surface in active region, then reverse current is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The Schottky electrode is positioned and formed on the active region surface before final device assembly and testing. The trench separation structure and floating region are prepared in advance to ensure proper electric field distribution. This preliminary formation of the Schottky junction allows for controlled creation of the metal-semiconductor interface, reducing reverse current while managing manufacturing precision requirements through structured preparation.
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 suppresses reverse current and improves breakdown voltage by uniformly distributing electric field intensity and avoiding pn-junction diode limitations, leading to enhanced device performance.
Implementation Method 1
a Schottky electrode which is connected to a portion that is exposed from the plurality of trench structures in the main surface
Data Source
AI summary
A semiconductor has a layer of a first conductivity type with a main surface, a trench separation structure which includes a separation trench formed in the main surface, a separation insulating film that covers a wall surface of the separation trench and a separation electrode that is embedded in the separation trench across the separation insulating film, the trench separation structure demarcating an outer region and an active region in the main surface, a floating region of a second conductivity type which is formed in an electrically floating state at a surface layer portion of the main surface along the trench separation structure in the outer region, and a Schottky electrode which is electrically connected to the separation electrode such as to retain the floating region in the electrically floating state in the outer region and which forms a Schottky junction with the main surface in the active region.