SiC Junction Termination Extension Doping via Beam Modifier
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Solution Overview
Problem
There is a need to simplify the formation of doped zones with laterally varying dopant concentrations in semiconductor materials where the diffusion length of dopants is low, as existing methods are complex and inefficient.
Innovation Solution
A beam modifier device with scattering and shading portions is used to modify particle beams, allowing for the formation of doped zones with varying dopant concentrations by altering the permeability and scattering of particles, enabling the creation of uniform and graded doping profiles in semiconductor substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple implants with different implant masks are used to form lateral junction termination extensions in semiconductor materials with low dopant diffusion length, then the dopant concentration varies with sufficient smoothness, but the process complexity increases significantly
Solution Approach 1:
The beam modifier device is divided into multiple scattering portions with different permeabilities arranged in a specific pattern. Each scattering portion acts as an independent element that contributes to the overall dopant distribution, allowing complex doping profiles to be achieved through simple geometric arrangement rather than multiple sequential implantation steps.
Solution Approach 2:
The beam modifier device serves as an intermediary component between the particle source and the semiconductor substrate. It modifies the particle beam in-flight by scattering particles through controlled permeability variations, thereby creating the desired dopant concentration profile without requiring complex mask patterns or multiple implantation steps.
2Device complexity
If a single implant with wedge-shaped or variable diameter masks is used to form graded junction termination extensions, then the process is simplified, but achieving precise dopant concentration gradients becomes difficult
Solution Approach 1:
Different regions of the beam modifier device are designed with locally optimized scattering properties. The scattering portions have spatially varying permeabilities that are tailored to produce specific dopant concentration gradients in different lateral regions of the semiconductor substrate, enabling precise control of the doping profile through local structural variations.
Solution Approach 2:
The permeability parameter of the beam modifier device is varied continuously or in steps across its surface area. By changing the permeability parameter spatially, the device controls the scattering angle and dopant flux distribution, thereby achieving precise dopant concentration gradients in a single implantation step without requiring complex mask geometries.
3Reliability
If lateral junction termination extensions with gradually decreasing dopant concentration are formed, then the blocking capability and breakdown voltage are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The beam modifier device is pre-configured with a specific pattern of scattering portions before the implantation process. This preliminary arrangement of scattering elements with varying permeabilities ensures that the desired graded dopant concentration profile is automatically formed during a single implantation step, eliminating the need for multiple sequential doping steps to achieve the same result.
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 approach facilitates the efficient formation of junction termination extensions with varying lateral doping, improving the blocking capability and reliability of semiconductor devices by creating smooth dopant concentration gradients and enhancing the breakdown voltage.
Implementation Method 1
Scattering portions scatter second partial beams of the particle beam, wherein cones of the second partial beams passing through neighboring ones of the scattering portions overlap in a semiconductor substrate
Implementation Method 2
In the scattering portions a total permeability for particles vertically impinging on an exposure surface of the beam modifier device changes along a lateral direction parallel to the exposure surface
Data Source
AI summary
A semiconductor device is provided that includes a silicon carbide substrate including a main surface at which a plurality of doped zones are formed in a junction termination extension zone of the silicon carbide substrate, the plurality of doped zones are arranged such that a lateral dopant concentration gradient is formed that decreases from a central region of the silicon carbide substrate to an outer edge region of the silicon carbide substrate.