RC-IGBT Diode Contact Layer for Lower Recovery Loss
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Solution Overview
Problem
Conventional reverse conducting IGBTs experience increased recovery loss due to high hole injection from the p+-type contact layer in the diode region, which affects the device's performance.
Innovation Solution
The semiconductor device incorporates a p-type contact layer with aluminum as p-type impurities in the diode region, reducing the thickness and impurity concentration to minimize hole injection and contact resistance, thereby reducing recovery loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a p+-type contact layer with high impurity concentration is provided at the anode part to reduce contact resistance, then contact resistance between surface electrode and anode part is reduced, but hole injection from the anode part increases and recovery loss increases
Solution Approach 1:
The patent changes the impurity concentration parameter of the contact layer from high (p+) to low (p-), thereby reducing hole injection and recovery loss while maintaining sufficient contact performance
Solution Approach 2:
The patent applies different impurity concentrations to different regions: the anode part uses low impurity concentration (p-) to reduce hole injection, while the cathode part uses high impurity concentration (n+) to ensure good contact, creating localized optimal properties for each function
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 use of aluminum in the p-type contact layer effectively lowers the recovery loss of the diode region while maintaining ohmic contact, improving the overall performance of the RC-IGBT.
Implementation Method 1
the amount of hole injection from the anode part increases in diode operation, and a recovery loss increases
Implementation Method 2
maintaining ohmic contact
Data Source
AI summary
A semiconductor device according to the present disclosure is an RC-IGBT in which an IGBT region 10 and a diode region 20 are provided adjacent to each other. The diode region 20 includes a p-type anode layer 25 provided on a first principal surface side of an n−-type drift layer 1, a p-type contact layer 24 provided on the first principal surface side of the p-type anode layer 25 and at a surface layer of a semiconductor substrate on the first principal surface side and connected with an emitter electrode 6, and an n+-type cathode layer 26 provided at a surface layer of the semiconductor substrate on a second principal surface side. The p-type contact layer 24 contains aluminum as p-type impurities, and the thickness of the p-type contact layer 24 is smaller than the thickness of an n+-type source layer 13 provided in the IGBT region 10.