Semiconductor Drain Termination with Conductive Trench Isolation
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Solution Overview
Problem
Integrated circuits with smart power technologies face challenges in maximizing voltage breakdown (VBD) while maintaining optimal resistance and design requirements, particularly in high-voltage applications, where increasing VBD often involves adding cost or process steps.
Innovation Solution
A semiconductor device architecture that forms a direct ohmic coupling between the drain region and conductive material within trench isolation structures, using metal interconnects or the same material for the trench isolation, enhances the depletion region's size and shape, thereby increasing VBD without additional cost or process complexity, and is portable across various core processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doping levels are optimized for RON and main device properties, then resistance is reduced, but voltage breakdown (VBD) becomes suboptimal
Solution Approach 1:
The patent divides the doping structure into multiple segments: a first doped region with first doping concentration and a second doped region with second doping concentration. This segmentation allows each region to be optimized independently - the first region for low resistance and the second region for high voltage breakdown, resolving the contradiction between RON optimization and VBD optimization.
2Reliability
If VBD is increased for high-voltage applications, then voltage breakdown is improved, but cost or process steps are added
Solution Approach 1:
The patent merges the formation of the second doped region with the existing drain region fabrication process. The second doped region is formed by extending the drain region doping into a deeper portion of the substrate, combining two functions (drain region formation and voltage breakdown enhancement) into a single process step, thereby improving VBD without adding process complexity or cost.
3Reliability
If a single doped region is used, then device structure is simple, but both RON and VBD cannot be simultaneously optimized
Solution Approach 1:
The patent applies local quality by creating different doping concentrations in different spatial regions. The first doped region has a higher doping concentration optimized for low resistance, while the second doped region has a lower doping concentration optimized for high voltage breakdown. This local differentiation allows simultaneous optimization of both RON and VBD without significantly increasing overall device complexity.
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 effectively increases the voltage breakdown while reducing resistance, enhancing the depletion region's size and shape, thus improving the robustness of semiconductor devices without adding cost or complexity, and is applicable across different semiconductor processes.
Implementation Method 1
The conductive trench filling material 104 is configured to increase the size of a depletion region 132 formed at a junction between the doped region and the drain region
Implementation Method 2
a connection structure formed between the conductive trench filling of the trench isolation structure and the drain region
Data Source
AI summary
Systems and methods of the disclosed embodiments include a semiconductor device having a semiconductor substrate. The semiconductor substrate has a first major surface, an opposing second major surface, a first doped region of a first conductivity type disposed beneath the first major surface, and a semiconductor region of the first conductivity type disposed between the first doped region and the second major surface. The semiconductor device may also include a trench isolation structure, comprising a conductive trench filling enclosed by an insulating trench liner. The trench isolation structure extends from the first major surface through the first doped region and into the semiconductor region. The semiconductor device may also include a semiconductor device structure disposed with a drain structure, and a connection structure formed between the conductive trench filling of the trench isolation structure and the drain region.