Oxide Semiconductor Transistor Electrodes for Heat-Resistant Stability
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Solution Overview
Problem
Existing transistors with oxide semiconductors face challenges in maintaining stable electrical characteristics, high reliability, and low leakage current due to impurities like water or hydrogen, requiring materials with heat resistance and oxidation resistance.
Innovation Solution
The use of conductors containing tungsten and elements like silicon, carbon, germanium, tin, aluminum, and nickel, with specific silicon concentrations and oxygen regions, provides heat resistance and oxidation resistance, enhancing transistor stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment at high temperature is performed to reduce impurities, then purity of the oxide semiconductor is improved, but the gate electrode, source electrode, or drain electrode may suffer from oxidation or degradation
Solution Approach 1:
The patent employs composite material structures for electrodes, specifically using tungsten nitride combined with other materials (such as tungsten, molybdenum, or their nitrides/oxynitrides) to create electrodes that simultaneously provide the necessary electrical conductivity and resistance to high-temperature oxidation. This composite approach allows the electrode to withstand the heat treatment required for impurity removal without degrading
Solution Approach 2:
The patent specifies precise compositional parameters for the electrode materials, including nitrogen content ratios (such as N/(W+N) greater than 0.5 in tungsten nitride layers) and thickness parameters. By controlling these material parameters, the electrode achieves optimal balance between electrical conductivity and oxidation resistance, enabling it to survive high-temperature processing while maintaining functionality
2Ease of manufacture
If conventional materials are used for electrodes, then ease of manufacture is improved, but heat resistance and oxidation resistance are insufficient
Solution Approach 1:
The patent modifies the material composition parameters of conventional electrode materials by introducing nitrogen into tungsten to form tungsten nitride with controlled nitrogen content. This parameter change transforms the material properties to achieve both high heat resistance and oxidation resistance while maintaining compatibility with existing manufacturing processes through sputtering deposition
Solution Approach 2:
The electrode structure uses composite materials combining tungsten nitride with other conductive materials (such as tungsten, molybdenum, or their compounds). This composite structure leverages the advantages of each material to achieve superior heat resistance and oxidation resistance compared to conventional single-material electrodes, while remaining manufacturable using standard semiconductor fabrication techniques
Data Source
AI summary
A transistor with favorable electrical characteristics is provided. One embodiment of the present invention is a semiconductor device including a semiconductor, a first insulator in contact with the semiconductor, a first conductor in contact with the first insulator and overlapping with the semiconductor with the first insulator positioned between the semiconductor and the first conductor, and a second conductor and a third conductor, which are in contact with the semiconductor. One or more of the first to third conductors include a region containing tungsten and one or more elements selected from silicon, carbon, germanium, tin, aluminum, and nickel.