Semiconductor Termination Trenches for Breakdown Voltage in Less Area
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices face challenges in reducing the lateral electric field, which affects performance, and require increased area for higher voltage devices, leading to reduced dies per wafer and increased costs.
Innovation Solution
A method for fabricating a termination structure for semiconductor devices involves creating doped-wells with a second dopant type in a substrate, forming trenches that expose the bottom and side surfaces of the doped-wells, and depositing an insulator material, such as polysilicon or silicon dioxide, into these trenches, which is surrounded by the exposed surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional termination structures are used to reduce lateral electric field, then breakdown voltage characteristics improve, but device area increases
Solution Approach 1:
The patent transitions from planar termination structures to three-dimensional trench-based structures. Trenches are formed extending into the substrate from the surface, creating vertical dimensionality that allows electric field management in multiple dimensions. This enables reduced lateral spread while maintaining breakdown voltage through the vertical trench walls lined with insulating material.
Solution Approach 2:
An insulating material is introduced as an intermediary substance within the trenches. This insulator acts as a mediator that shapes and controls the electric field distribution, allowing the termination structure to achieve improved breakdown voltage characteristics without requiring increased device area. The insulator fills the trench space and provides electrical isolation and field control.
2Productivity
If device area is reduced to increase dies per wafer, then productivity improves, but lateral electric field control deteriorates
Solution Approach 1:
By introducing vertical trenches into the substrate, the patent moves electric field control from a two-dimensional planar problem to a three-dimensional solution. The trenches extend downward into the substrate, confining and managing the electric field in the vertical dimension, which allows for reduced device footprint while maintaining effective lateral electric field control.
Solution Approach 2:
The patent changes the geometric parameters of the termination structure by introducing depth (vertical dimension) rather than relying solely on lateral dimensions. The trench depth, width, and insulator material properties are optimized to achieve the desired electric field control with reduced area, enabling higher dies per wafer while maintaining lateral electric field management.
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 termination structure effectively reduces the lateral electric field, improves breakdown voltage characteristics, and reduces the area required for higher voltage devices, thereby increasing the number of dies per wafer and reducing costs.
Implementation Method 1
depositing a material into respective ones of the formed trenches, wherein the deposited material in respective ones of the formed trenches is surrounded by the exposed bottom surface of the doped-wells of the respective formed trench and the exposed side surfaces of the doped-wells of the respective formed trench
Data Source
AI summary
A termination structure for a semiconductor device that may include a substrate having a first type dopant. A plurality of doped-wells having a second type dopant formed in the substrate. A plurality of trenches formed into the plurality of doped-wells, respective ones of the formed trenches exposing a bottom surface of the doped-well, and exposing side surfaces of the doped-well, and a material within respective ones of the formed trenches, wherein the material in respective ones of the formed trenches is surrounded by the exposed bottom surface of the doped-well of the respective formed trench and the exposed side surfaces of the doped-well of the respective formed trench.