Fast Recovery Diode With Integrated Resistor for Soft Reverse Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current FRD manufacturing techniques require platinum diffusion, which contaminates modern wafer fabrication facilities, leading to reduced production capacity and potential shortages, necessitating alternative methods to reduce reverse recovery current and charge without using platinum.
Innovation Solution
Integration of a current limiting resistor (CLR) made of polysilicon or resistive semiconductor regions within the FRD structure, which reduces reverse recovery current and charge without requiring platinum diffusion, and includes a manufacturing process that avoids contaminating MOSFET fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum diffusion is used to reduce reverse recovery current and charge, then the reverse recovery performance is improved, but the manufacturing facility becomes contaminated and production capacity is reduced
Solution Approach 1:
The patent extracts the harmful platinum diffusion process from the manufacturing workflow and replaces it with an alternative approach using a carrier storage region created through selective epitaxial growth and ion implantation. This removes the contamination source while maintaining the reverse recovery performance improvement.
Solution Approach 2:
The patent changes the manufacturing parameters by using selective epitaxial growth to create a carrier storage region with specific doping concentrations and thicknesses, combined with controlled ion implantation (gold or platinum) at specific doses and energies. This achieves the desired reverse recovery characteristics without requiring extensive platinum diffusion that contaminates facilities.
2Reliability
If platinum diffusion is used to achieve soft recovery, then reverse recovery current is reduced, but manufacturing complexity and contamination control become more difficult
Solution Approach 1:
The patent segments the manufacturing process into distinct stages: first creating the carrier storage region through selective epitaxial growth, then applying controlled ion implantation. This segmentation allows for better process control and reduces contamination issues compared to extensive platinum diffusion.
Solution Approach 2:
The patent introduces a carrier storage region as an intermediary structure between the anode and the main diode junction. This intermediate layer serves as a controlled reservoir for minority carriers, enabling soft recovery without requiring heavy reliance on platinum diffusion processes.
3Ease of manufacture
If older 6-inch wafer fabrication equipment is used for FRD manufacture, then platinum diffusion can be performed, but production capacity is reduced
Solution Approach 1:
The patent changes the manufacturing parameters to be compatible with modern 8-inch and 12-inch wafer fabrication equipment by using selective epitaxial growth and controlled ion implantation instead of platinum diffusion. This allows production on larger wafers, significantly increasing production capacity while maintaining FRD performance.
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
The CLR-FRD design effectively minimizes reverse recovery current and charge, enabling efficient production in modern facilities and supporting high-speed switching operations without the need for platinum diffusion, thus addressing production capacity limitations.
Implementation Method 1
An integrated resistor, sometimes referred to herein as a current limiting resistor (CLR), that reduces the reverse recovery current and charge of the FRD
Implementation Method 2
Platinum (Pt) diffusion, helium (He) implantation, high energy implantation of neutrons or protons, or electron beam irradiation may be used to create the desired defect levels in the semiconductor structure of an FRD
Implementation Method 3
Platinum (Pt) diffusion, helium (He) implantation, high energy implantation of neutrons or protons, or electron beam irradiation may be used to create the desired defect levels in the semiconductor structure of an FRD
Implementation Method 4
Platinum (Pt) diffusion, helium (He) implantation, high energy implantation of neutrons or protons, or electron beam irradiation may be used to create the desired defect levels in the semiconductor structure of an FRD
Data Source
AI summary
A fast recovery diode may include: a first semiconductor structure including a first layer having a first conductivity type; a first electrode contacting a bottom surface of the first layer; a second semiconductor structure including a second layer having a second conductivity type, the second layer contacting the first semiconductor structure to form a junction; a second electrode of the diode, the second electrode overlying the second semiconductor structure; and a resistive semiconductor region providing a current path between the second electrode and the second semiconductor structure. The resistive semiconductor region may be formed in the second layer with an underlying buried layer defining a current path through the resistive semiconductor region or may be formed of polysilicon with insulating layers defining a current path through the resistive semiconductor region.