Semiconductor Resistive Element Material Selection for Temperature Stability
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Solution Overview
Problem
Conventional semiconductor devices with silicon-based resistive elements face significant temperature-dependent resistance variations, making them unsuitable for high-frequency signal processing due to large resistance temperature coefficients and sheet resistance values.
Innovation Solution
The semiconductor device incorporates a multilayer wiring layer with a resistive element made from materials like titanium, titanium nitride, tantalum, tantalum nitride, tungsten, or silicon chromium, which are spaced apart from the optical modulator and integrated with a capacitive element to form an equalizer circuit, reducing temperature dependence and enhancing high-frequency signal handling capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a silicon-based resistive element is used in the semiconductor device, then the device can be manufactured with conventional silicon fabrication processes, but the resistance value varies significantly with temperature changes
Solution Approach 1:
The patent changes the material parameter of the resistive element from silicon to materials with low temperature coefficients of resistance (TCR), specifically tungsten (TCR: -0.003 to -0.005), molybdenum (TCR: -0.004 to -0.006), or tantalum (TCR: -0.002 to -0.004). This material substitution maintains compatibility with conventional semiconductor fabrication processes while achieving resistance stability across temperature variations, directly resolving the contradiction between ease of manufacture and resistance stability.
2Area of stationary object
If the resistive element is placed close to the optical modulator, then the device area is reduced, but the temperature dependence of resistance increases due to heat from the modulator
Solution Approach 1:
The patent introduces an insulating layer as an intermediary between the optical modulator and the resistive element. This insulating layer acts as a thermal barrier that reduces heat transfer from the modulator to the resistive element, thereby maintaining resistance stability while allowing the components to be positioned in close proximity to minimize device area. The insulating layer mediates the thermal interaction between the two components, resolving the contradiction between area reduction and resistance stability.
3Ease of manufacture
If conventional silicon resistive elements are used, then the manufacturing process is simple, but the sheet resistance value is too high for effective high-frequency signal processing
Solution Approach 1:
The patent changes the electrical parameter (sheet resistance) by selecting materials with inherently lower resistivity than silicon. The specified materials—tungsten, molybdenum, and tantalum—provide sheet resistance values suitable for high-frequency signal processing while maintaining compatibility with standard semiconductor manufacturing techniques. This material parameter change resolves the contradiction between manufacturing simplicity and signal processing effectiveness.
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 stabilizes resistance values and reduces temperature dependence, enabling effective treatment of high-frequency signals while maintaining a high resistance value, thus improving the semiconductor device's characteristics.
Implementation Method 1
the resistance value of the resistive element made of silicon varies depending on a temperature change
Data Source
AI summary
A semiconductor device includes a first insulating layer, an optical modulator, and a multilayer wiring layer. The optical modulator is formed on the first insulating layer. The multilayer wiring layer is formed on the first insulating layer and including a wiring and a resistive element which are spaced apart from each other. The resistive element is formed without overlapping with the optical modulator in plan view. A material of the resistive element is at least one selected from the group consisting of titanium, titanium nitride, tantalum, tantalum nitride, tungsten, and silicon chromium.