Power Semiconductor Edge Termination via Mandrel Doping
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Solution Overview
Problem
Existing power semiconductor devices face challenges in creating doped semiconductor regions within edge termination regions with precise shape definition at low costs, without requiring fine-resolution lithography techniques, which affects the reliability of electric field control and blocking capability.
Innovation Solution
A power semiconductor device design featuring a doped semiconductor region with a first implanted dopant dose of one conductivity type compensated by a second implanted dopant dose of complementary conductivity type, where the second dopants have a smaller lateral extension, forming a continuous pn-junction and reducing the waviness of the net dopant concentration, achieved through specific masked implantation and diffusion processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional doped semiconductor regions are created using standard lithography techniques, then manufacturing cost is reduced, but shape definition precision deteriorates
Solution Approach 1:
The patent applies preliminary action by forming a mandrel structure before the actual doping process. This mandrel serves as a pre-prepared template that guides subsequent doping steps, enabling precise shape definition without requiring high-resolution lithography. The mandrel is formed in advance and used to define the geometry of the doped region, thereby achieving high manufacturing precision at lower cost.
Solution Approach 2:
The mandrel acts as an intermediary element between the lithography process and the final doped region. Instead of directly patterning the doped region with expensive fine-resolution lithography, the mandrel mediates the process by providing a sacrificial structure that defines the shape. After doping, the mandrel is removed, leaving the precisely defined doped region without requiring advanced lithography capabilities.
2Reliability
If doped semiconductor regions are created with fine shape definition, then electric field control is improved, but manufacturing complexity increases
Solution Approach 1:
The mandrel is formed in advance as a preliminary structure that simplifies the overall manufacturing process. By preparing the shape-defining template beforehand, the patent reduces the complexity of subsequent doping steps while ensuring precise electric field control. The preliminary mandrel formation allows standard lithography to be used instead of complex multi-step processes.
Solution Approach 2:
The mandrel serves as a temporary intermediary that enables precise doping without increasing manufacturing complexity. It provides the necessary shape definition during the doping process and is subsequently removed, leaving a simple final structure. This intermediary approach avoids the need for complex in-situ patterning techniques.
3Manufacturing precision
If standard lithography techniques are used for doping, then production cost is reduced, but dopant distribution uniformity deteriorates
Solution Approach 1:
The mandrel is formed in advance with precise geometry that defines the desired dopant distribution. This preliminary structure ensures uniform dopant distribution by providing consistent physical constraints during the doping process, eliminating the need for expensive fine-resolution lithography to achieve uniformity.
Solution Approach 2:
The mandrel acts as an intermediary that translates simple lithography patterns into precise dopant distributions. During doping, the mandrel mediates the interaction between the dopant source and the semiconductor substrate, ensuring uniform distribution through its geometric constraints without requiring advanced lithography capabilities.
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 results in a more homogeneous dopant distribution and improved electric field control, enhancing the blocking capability of the power semiconductor device while reducing production costs and complexity.
Implementation Method 1
a part of a first implanted dopant dose of one conductivity type (e.g., p-type) is compensated by a second implanted dopant dose of the complementary conductivity type (e.g., n-type). As a result, a waviness of a vertically integrated net dopant concentration of the doped semiconductor region is reduced.
Data Source
AI summary
A power semiconductor device includes: a semiconductor body having a front side surface and a drift region having first conductivity type dopants; and an edge termination region that includes a part of the drift region and a first semiconductor region extending along the front side surface. The first semiconductor region includes dopants of both conductivity types and forms a continuous pn-junction with the drift region. An integrated vertical dopant concentration of the second conductivity type dopants is higher than an integrated vertical dopant concentration of the first conductivity type dopants within the first semiconductor region. A first dose profile representing a vertically integrated net dopant concentration of the both conductivity type dopants in the first doped semiconductor region has a smaller degree of waviness along a horizontal direction than a second dose profile representing a vertically integrated dopant concentration of the second conductivity type dopants in the same semiconductor region.