Semiconductor Device With Hydrogen Ion Irradiated Storage Regions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices, such as IGBTs, face challenges in optimizing the distribution of hydrogen donors and crystal defects to enhance carrier lifetime and reduce ON resistance, while maintaining effective carrier mobility and suppressing crystal defects in channel forming regions.
Innovation Solution
A semiconductor device with a specific doping concentration distribution of hydrogen donors and crystal defects, where hydrogen donors are introduced at a peak concentration deeper in the substrate and crystal defects are formed closer to the back surface, forming storage regions and a carrier lifetime killer region to improve carrier lifetime and mobility, and reduce ON resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen donors are introduced deeper in the substrate to form storage regions, then carrier lifetime is enhanced and ON resistance is reduced, but crystal defects may form in channel forming regions
Solution Approach 1:
The patent applies local quality by creating distinct spatial zones with different hydrogen donor concentrations and crystal defect densities. The storage region deeper in the substrate has high hydrogen concentration for carrier accumulation, while the channel forming region near the surface maintains low crystal defect density to preserve carrier mobility. This spatial differentiation of properties resolves the contradiction between enhancing carrier lifetime through deep hydrogen introduction and preventing crystal defects in the channel region.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a single-layer structure to a multi-layer vertical structure with distinct functional zones. By introducing hydrogen donors at specific depth positions to form storage regions separated from channel forming regions by distance, the patent uses the depth dimension to simultaneously achieve high carrier lifetime in the storage region and low crystal defect density in the channel region, thus resolving the contradiction between these two requirements.
2Manufacturing precision
If multiple separate processes are used to form storage regions and carrier lifetime killer regions, then precise control of doping distribution is achieved, but manufacturing complexity and time increase
Solution Approach 1:
The patent merges the formation of storage regions and carrier lifetime killer regions into a single hydrogen ion irradiation process. By controlling the irradiation conditions and depth distribution, both functional regions are created simultaneously in one step, eliminating the need for separate processing steps. This merging maintains precise control over doping concentration distribution while significantly improving manufacturing efficiency and reducing process complexity.
Solution Approach 2:
The patent makes the hydrogen ion irradiation process multi-functional by designing it to simultaneously create both storage regions and carrier lifetime killer regions with different characteristics. A single irradiation process achieves multiple objectives: forming deep storage regions for carrier accumulation and creating shallower carrier lifetime killer regions for mobility control, thus improving productivity without sacrificing manufacturing precision.
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 solution effectively enhances carrier lifetime, reduces ON resistance, and suppresses crystal defects, leading to improved electrical characteristics and manufacturing efficiency by simplifying the process through concurrent hydrogen ion irradiation from the back surface.
Implementation Method 1
the storage region is formed by proton (H+) implantation
Implementation Method 2
the carrier lifetime killer region is formed by electron beam irradiation
Data Source
AI summary
Directly beneath p−-type base regions, n-type storage regions are provided. The storage regions contain hydrogen donors as an impurity and have an impurity concentration higher than that of the n−-type drift region. The storage regions are formed by hydrogen ion irradiation from a back surface of a semiconductor substrate. The storage regions have a peak hydrogen concentration and are at positions that coincide with where the hydrogen ions have been irradiated. By the hydrogen ion irradiation, a crystal defect region that is a carrier lifetime killer region is formed concurrently with the storage regions, closer to the back surface of the semiconductor substrate than are storage regions. The crystal defect region has a crystal defect density with a peak density at a position closer to the back surface of the semiconductor substrate than are the storage regions. A semiconductor device having such storage regions and a carrier lifetime killer region is enabled.