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Detailed Comparison of Diffused Silicon, Ceramic, Capacitive, and Monocrystalline Silicon Pressure Sensors
Pressure sensors are core components in the field of industrial automation and are widely used in petrochemical, hydraulic systems, water conservancy, pharmaceuticals, aerospace, and other industries. According to different sensing elements and operating principles, the mainstream types include four categories: diffused silicon (piezoresistive diffused silicon), ceramic piezoresistive, ceramic capacitive, and monocrystalline silicon. These sensors exhibit significant differences in accuracy, temperature stability, cost, overload resistance, and measurement range.
This article systematically compares the operating principles, key performance characteristics, advantages and disadvantages, and typical applications of these four sensor types to help engineers make quick and informed selection decisions.
Comparison of Operating Principles
1. Diffused Silicon Pressure Sensor (Oil-Filled Piezoresistive Type)
Pressure is transmitted through a stainless-steel isolation diaphragm and silicone oil to the diffused silicon chip. Piezoresistors diffused on the chip form a Wheatstone bridge. When force is applied, resistance changes and outputs an mV-level signal.
2. Ceramic Piezoresistive Pressure Sensor
Thick-film resistors are directly printed on a ceramic substrate (typically alumina) to form a piezoresistive bridge. Pressure causes deformation of the ceramic diaphragm, resulting in resistance changes and signal output. It features a dry structure without silicone oil filling.
3. Ceramic Capacitive Pressure Sensor (Mainstream for Differential Pressure / Low Range)
A ceramic diaphragm and a fixed electrode form a variable capacitor. Pressure-induced diaphragm displacement changes the capacitance value, which is then converted into signals such as 4–20 mA. The structure may be dry or partially filled with inert media.
4. Monocrystalline Silicon Pressure Sensor (High-Accuracy Piezoresistive)
Uses a high-purity monocrystalline silicon chip with a more precise piezoresistive bridge, typically manufactured using MEMS technology. Most designs use oil-filled isolation structures, and some high-end models support absolute and differential pressure measurement.
Performance Comparison Table (Key Indicators)
| Item | Diffused Silicon (Oil-Filled) | Ceramic Piezoresistive | Ceramic Capacitive | Monocrystalline Silicon (High Performance) |
|---|---|---|---|---|
| Working Principle | Piezoresistive (Silicon Chip) | Piezoresistive (Ceramic Thick Film) | Capacitive (Ceramic Diaphragm) | Piezoresistive (Monocrystalline Silicon) |
| Accuracy | 0.1%–0.25% FS | 0.25%–0.5% FS | 0.075%–0.15% FS | 0.05%–0.1% FS |
| Temperature Stability | Moderate (Compensation Required) | Excellent (-40 to 135°C) | Outstanding | Excellent |
| Measurement Range | Medium to High | Medium to Ultra-High | Low to Medium (Strong in Differential) | Medium to High |
| Overload Resistance | Excellent (200%–1000%) | Moderate to Excellent | Moderate (10–50x) | Excellent |
| Long-Term Stability | Good | Excellent | Outstanding | Outstanding |
| Cost | Medium | Low to Medium | Medium to High | High |
| Media Compatibility | Requires Isolation Diaphragm | Direct Ceramic Contact (Corrosion Resistant) | Direct Ceramic Contact (Corrosion Resistant) | Requires Isolation Diaphragm |
| Typical Applications | Industrial Process, Hydraulics | General Industry, Water Treatment | Differential Pressure, Clean Environments | High-Accuracy Process Control, Differential Pressure |
Advantages, Disadvantages, and Application Scenarios
Diffused Silicon Pressure Sensors
Advantages: High cost-performance ratio, strong overload resistance, fast dynamic response, easy miniaturization.
Disadvantages: Relatively large temperature drift (requires effective compensation circuits).
Applications: Mid-range industrial applications, hydraulic systems, oil and gas pipeline pressure measurement.
Ceramic Piezoresistive Pressure Sensors
Advantages: Low cost, corrosion resistance, impact resistance, vibration resistance, wide temperature range, oil-free structure (no leakage risk).
Disadvantages: Slightly lower accuracy than monocrystalline silicon, difficult to achieve ultra-low pressure ranges.
Applications: Water treatment, HVAC, compressors, general industrial pressure measurement (especially high ranges).
Ceramic Capacitive Pressure Sensors
Advantages: Outstanding temperature stability, minimal long-term drift, ideal for low-range and high-accuracy differential pressure measurement, good overpressure tolerance.
Disadvantages: Lower overload resistance than piezoresistive types, higher cost.
Applications: Differential pressure transmitters (liquid level, flow), pharmaceuticals, clean rooms, micro and low pressure measurement.
Monocrystalline Silicon Pressure Sensors
Advantages: Highest accuracy, best long-term stability, excellent temperature compensation, strong anti-interference capability.
Disadvantages: Highest cost, complex manufacturing process.
Applications: High-end process control, precision instruments, aerospace, applications requiring accuracy better than 0.1%.
In differential pressure transmitters, ceramic capacitive and monocrystalline silicon sensors are the mainstream choices (using silicone oil or inert gas for pressure transmission), while standard gauge or absolute pressure transmitters commonly use diffused silicon or ceramic piezoresistive sensors.
Selection Recommendations
Limited budget + medium accuracy → Diffused silicon or ceramic piezoresistive
Low range / high stability / differential pressure → Ceramic capacitive
High accuracy / high reliability / long-term stability → Monocrystalline silicon (premium choice)
Corrosive media + shock and vibration environments → Ceramic series preferred
Actual selection should also consider media characteristics, temperature range, pressure range, installation method, and explosion-proof requirements.
Conclusion
Diffused silicon, ceramic, capacitive, and monocrystalline silicon pressure sensors each have their own strengths. There is no absolute superiority—only the most suitable application scenario. Understanding their core differences helps enterprises achieve the best balance between cost, performance, and reliability. With advances in MEMS technology and material science, these sensors continue to evolve toward higher accuracy, wider temperature ranges, and stronger environmental adaptability.
If you have specific application requirements (such as range, media, or accuracy), feel free to discuss the most suitable pressure sensor solution further.
