Angled Trench Super Junction Transistor Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing transistor designs without super junctions face challenges in reducing resistance and increasing breakdown voltage, as they lack efficient alternating conductivity type regions and uniform dopant distribution.
Innovation Solution
The implementation of a super junction in a transistor, featuring a doped substrate with an angled trench and epitaxial layer, where the angled trench's sidewalls are angled between 85-degrees to 89-degrees, allowing for a doped body with opposite dopant type to be formed, enhancing dopant distribution and breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a straight walled trench is used to form super junction, then the manufacturing process is simpler, but the dopant distribution is less uniform and breakdown voltage is lower
Solution Approach 1:
The patent applies asymmetry by changing the trench sidewalls from vertical to angled (85-89 degrees relative to substrate surface). This asymmetric geometry enables the ion implantation process to achieve uniform dopant distribution throughout the trench volume, resolving the contradiction between manufacturing simplicity and dopant uniformity.
Solution Approach 2:
The patent changes the geometric parameter of the trench from vertical to angled sidewalls. This parameter modification transforms the ion implantation process outcome, allowing uniform dopant distribution to be achieved through standard manufacturing processes rather than requiring complex additional steps.
2Reliability
If the trench depth is increased to improve breakdown voltage, then breakdown voltage increases, but manufacturing difficulty increases with angled trenches
Solution Approach 1:
The angled sidewall design creates an asymmetric trench geometry that facilitates deeper trench formation. The angle optimization (85-89 degrees) specifically addresses the manufacturing challenge by enabling standard etching and filling processes to achieve greater depths while maintaining process control and uniformity.
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 results in a higher breakdown voltage and more uniform dopant distribution, improving the transistor's performance by increasing the depth of the angled trench, which enhances the breakdown voltage and reduces resistance.
Implementation Method 1
the trench openings are subjected to a tilted ion implantation process to introduce a dopant species opposite to that of the doped substrate
Implementation Method 2
The trench opening is then filled by one or more epitaxial depositions in order to form the alternating conductivity type regions
Data Source
AI summary
A super junction includes a substrate and an epitaxial layer over the substrate, the epitaxial layer having a first dopant type. The super junction further includes an angled trench in the epitaxial layer, the angled trench having sidewalls disposed at an angle ranging from about 85-degrees to about 89-degrees with respect to a top surface of the epitaxial layer. The super junction further includes a doped body in the epitaxial layer surrounding the angled trench, the doped body having a second dopant type, the second dopant type opposite that of the first dopant type.