Thyristor Double-Sided Mesa Vertical Junctions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thyristors, such as silicon controlled rectifiers (SCRs), suffer from high reverse leakage current, which decreases their reliability and increases manufacturing costs due to reduced yield.
Innovation Solution
A thyristor with a double-sided mesa structure is fabricated, where the gate and anode regions extend laterally beyond their respective mesa structures into the semiconductor substrate, forming vertical junctions instead of horizontal ones, thereby reducing leakage current and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If horizontal junctions are used in conventional thyristor structure, then manufacturing is simpler, but leakage current increases and reliability decreases
Solution Approach 1:
The patent transitions from horizontal junctions to vertical junctions by extending gate and anode regions downward into the semiconductor substrate below the mesa structures. This dimensional change from horizontal to vertical configuration reduces the junction area exposed to reverse bias, thereby decreasing leakage current and improving reliability while maintaining manufacturability through standard semiconductor processing techniques.
2Reliability
If gate and anode regions are extended laterally beyond mesa structures, then leakage current decreases, but manufacturing precision requirements increase
Solution Approach 1:
The patent forms the extended gate and anode regions before creating the mesa structures. By performing the region extension preliminary to mesa formation, the critical dimensional tolerances are established earlier in the process when subsequent steps can accommodate variations, thereby reducing the cumulative precision requirements while achieving the desired leakage current reduction.
Data Source
AI summary
A thyristor and a method for manufacturing the thyristor that includes a gate region extending from the first major surface into a semiconductor substrate and an anode region extending from the second major surface into the semiconductor substrate. A cathode region extends into a portion of the gate region. Optionally, enhanced doped regions extend into the gate and anode regions. A mesa structure having a height HG is formed from the first major surface and a mesa structure having a height HA is formed from the second major surface. The gate region extends under the first major surface of the semiconductor substrate and it extends vertically into the semiconductor substrate a distance that is greater than height HG. The anode region extends under the second major surface of the semiconductor substrate and it extends vertically into the semiconductor substrate a distance that is greater than height HA.