GaN Polarization Super Junction Layout for Vertical Current Flow
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Solution Overview
Problem
Existing semiconductor devices with a polarization super junction (PSJ) structure face limitations on electrode width and thickness due to the arrangement of electrodes on a single surface, restricting current flow and increasing manufacturing complexity.
Innovation Solution
The semiconductor device incorporates a polarization super junction structure arranged along the planar direction of a gallium nitride substrate, allowing electrodes to be disposed on opposite surfaces, enabling current flow in the thickness direction and reducing limitations on electrode size and manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electrodes are arranged on a single surface in existing semiconductor devices with PSJ structure, then the device structure is simpler, but the electrode width and thickness are limited and current flow is restricted
Solution Approach 1:
The patent transitions from arranging electrodes on a single surface (2D arrangement) to arranging electrodes on opposite surfaces (3D arrangement through the substrate thickness). This dimensional change allows electrodes to extend through the substrate, enabling larger electrode width and thickness without increasing planar complexity, thereby resolving the contradiction between structural simplicity and electrode size limitations.
2Ease of manufacture
If electrodes are arranged on a single surface, then manufacturing process is simpler, but manufacturing complexity increases due to electrode size limitations
Solution Approach 1:
By moving electrode arrangement to opposite surfaces of the substrate, the patent enables current flow in the thickness direction without complicating the manufacturing process. The epitaxial growth method naturally forms the PSJ structure with alternating column regions, and electrodes are simply formed on opposite surfaces, avoiding complex multi-step processing while eliminating manufacturing complexity associated with single-surface electrode constraints.
3Device complexity
If current flows in the plane direction, then electrode arrangement is simpler, but breakdown voltage characteristics are limited
Solution Approach 1:
The patent changes current flow from in-plane direction to thickness direction by arranging electrodes on opposite surfaces. This vertical current path through the PSJ structure with alternating high-bandgap and low-bandgap column regions enhances breakdown voltage characteristics while maintaining simple electrode arrangement, as electrodes are directly formed on opposite substrate surfaces without complex lateral routing.
4Length of moving object
If electrodes are disposed on opposite surfaces, then current flow in thickness direction is enabled, but device structure becomes more complex
Solution Approach 1:
The patent utilizes the thickness dimension of the substrate to arrange electrodes on opposite surfaces, enabling current flow through the PSJ structure. The underlying GaN substrate with alternately arranged first and second column regions provides the structural framework, while electrodes on opposite surfaces simply cap this structure, achieving extended current path without proportionally increasing overall device structural complexity.
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 configuration enhances breakdown voltage characteristics, reduces electrode limitations, and simplifies the manufacturing process while facilitating large current flow and improved reliability of the gate insulating film.
Implementation Method 1
polarization super junction (hereafter, also simply referred to as PSJ) structure including a first nitride semiconductor layer and a second nitride semiconductor layer laminated on a substrate
Data Source
AI summary
A semiconductor device includes a semiconductor substrate including a semiconductor element, a first surface-side electrode disposed on a first surface of the semiconductor substrate, and a second surface-side electrode disposed on a second surface of the semiconductor substrate. The semiconductor substrate includes a gallium nitride substrate and first column regions and second column regions disposed on a first principal surface of the gallium nitride substrate and alternately arranged along a c-axis direction in the first principal surface. The first column regions are formed of a first nitride semiconductor layer and the second column regions are formed of a second nitride semiconductor layer that is higher in band gap than the first nitride semiconductor layer. The semiconductor element is configured to enable a current to flow between the first surface and the second surface of the semiconductor substrate.