Oxide Semiconductor Power Diode Structure for Heat and Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices for high power applications face challenges such as difficulty in obtaining high-quality silicon carbide crystals, high process temperatures, and issues with forming insulating layers due to carbon content, as well as heat dissipation problems when high current flows, leading to suboptimal electrical characteristics like reverse saturation current and withstand voltage.
Innovation Solution
A semiconductor device is designed with a structure that includes a first electrode, a gate insulating layer, an oxide semiconductor layer overlapping with the first electrode, and a pair of second electrodes that act as a heat sink, with n+ layers to reduce contact resistance, and a crystalline oxide semiconductor layer with specific thickness and composition to enhance electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon carbide is used for high power semiconductor devices, then withstand voltage and reverse saturation current characteristics are improved, but manufacturing complexity and process temperature requirements increase
Solution Approach 1:
The patent changes the material parameter from silicon carbide to oxide semiconductor, which fundamentally alters the manufacturing parameters. This allows processing at lower temperatures and simplifies the manufacturing process while maintaining or improving electrical characteristics including withstand voltage
Solution Approach 2:
The patent employs a simpler manufacturing approach using oxide semiconductors that can be processed more easily and at lower costs compared to silicon carbide, making high power devices more economically viable
2Reliability
If ion implantation is used to form impurity regions in silicon carbide, then electrical characteristics are improved, but heat treatment at high temperature is required to repair crystal defects
Solution Approach 1:
The patent changes the material system from silicon carbide to oxide semiconductor, which allows for different doping and impurity introduction methods that do not require high-temperature annealing to repair crystal defects, thus reducing the temperature parameter
3Reliability
If thermal oxidation is used to form insulating layers, then insulating layer quality is improved, but carbon content in silicon carbide prevents good quality insulating layer formation
Solution Approach 1:
The patent changes the semiconductor material from carbon-containing silicon carbide to oxide semiconductor, which is compatible with thermal oxidation processes and allows formation of high quality insulating layers without the carbon contamination problem
4Power
If high current flows through the semiconductor device, then power handling capability is improved, but heat generation increases requiring thermal dissipation structures
Solution Approach 1:
The patent converts the harmful heat generated by high current into a manageable parameter by using the oxide semiconductor's inherent properties and device structure to dissipate heat effectively, turning the heat problem into a controlled thermal management issue
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 provides a semiconductor device with improved high withstand voltage, low reverse saturation current, and high on-state current capabilities, while also effectively dissipating heat generated during high current flow, thereby enhancing the reliability and performance of the device.
Implementation Method 1
the pair of second electrodes serve as a heat sink, and when heat is generated due to current flowing in the oxide semiconductor layer including the channel formation region, the pair of second electrodes can dissipate the heat to the outside
Implementation Method 2
n+ layers are provided between the gate insulating layer and the end portions of the oxide semiconductor layer, and the pair of second electrodes, in order to reduce contact resistance between the pair of second electrodes and the oxide semiconductor layer
Data Source
AI summary
An object is to provide a semiconductor device having electrical characteristics such as high withstand voltage, low reverse saturation current, and high on-state current. In particular, an object is to provide a power diode and a rectifier which include non-linear elements. An embodiment of the present invention is a semiconductor device including a first electrode, a gate insulating layer covering the first electrode, an oxide semiconductor layer in contact with the gate insulating layer and overlapping with the first electrode, a pair of second electrodes covering end portions of the oxide semiconductor layer, an insulating layer covering the pair of second electrodes and the oxide semiconductor layer, and a third electrode in contact with the insulating layer and between the pair of second electrodes. The pair of second electrodes are in contact with end surfaces of the oxide semiconductor layer.