Silicon Capacitors
1. What are Silicon Capacitors?
Silicon Capacitors are new capacitors made of silicon as the base material through semiconductor technology. Its structure is mainly divided into two categories:
MIS Structure (metal/insulator/semiconductor): for high voltage and low capacity scenarios;
MOS Structure (metal/oxide/semiconductor): for low voltage and high capacity scenarios, typical applications include laser radar (LiDAR) and advanced process chips.
The core process uses 3D nanotechnology to form a high aspect ratio electrode structure through dry etching (such as the BOSCH process), significantly increasing the surface area to improve the electrostatic capacitance.
2. What are the Technical Advantages of Silicon Capacitors?
Compared with traditional capacitors (such as MLCC), silicon capacitors have the following characteristics:
High Stability: Temperature tolerance range up to 250°C, suitable for high-temperature environments (such as automobiles, aerospace);
High-Frequency Characteristics: Ultra-low insertion loss and ESL (equivalent series inductance), suitable for high-frequency scenarios such as optical communication and RF power amplifiers;
Non-polarity: Simplify circuit design and reduce the risk of misoperation;
Miniaturization: Standardized thickness can be up to 100 microns, and customized thickness can be as thin as 40~50 microns.
3. What are Silicon Capacitors Used for?
Automotive Electronics: Realize low ESL characteristics in LiDAR sensors to improve detection distance and resolution;
Medical Equipment: Support high reliability and low power consumption requirements through customized IPD (integrated passive devices);
Optical Communication and Base Stations: Maintain low power consumption and small size at ultra-high frequencies to help optimize 5G/6G network equipment;
Industrial and Aerospace: High-temperature resistance is suitable for harsh environments such as oil exploration and spacecraft electronic systems.
4. Comparison with Traditional Capacitors
Material Differences: Silicon is used to replace ceramics or electrolytes to avoid the piezoelectric effect of traditional capacitors (no whistling problem);
Performance Improvement: MLCC capacitance is prone to attenuation at high temperatures or high frequency, while silicon capacitors remain stable;
Reliability: Semiconductor-grade processes ensure longer service life and vibration resistance.
5. Technological Development of Silicon Capacitors
Murata and other manufacturers have already achieved mass production of silicon capacitors, and its subsidiary MIPS has further improved capacitance density through a multi-layer MIM structure (metal/insulator/metal). In the future, with the evolution of semiconductor technology, silicon capacitors are expected to replace traditional capacitors in more fields.
Silicon Capacitors FAQs
1) What dielectric materials are used in silicon capacitors?
Silicon capacitors use silicon-based oxides (such as SiO₂) and nitrides (such as Si₃N₄) as dielectric materials. Their advantages are high reliability, thermal stability, and voltage stability, and they are suitable for harsh environments.
2) What are the packaging forms of silicon capacitors?
Welding Installation: Suitable for high-density integration scenarios, such as ultra-thin mobile devices.
Wire Bonding Installation: Can be integrated with IC packaging, suitable for processors, RF modules, etc.
3) How do we verify the reliability of silicon capacitors?
Murata evaluates the reliability of silicon capacitors through the following tests: Oxide film destruction test (TDDB): Verify the long-term stability of dielectric materials.
Temperature cycle test (TMCL): Test performance under extreme temperatures.
4) How do silicon capacitors perform in high-temperature environments?
Silicon capacitors can work stably at temperatures up to 250°C, and the capacitance value is almost unaffected by temperature changes, making them suitable for aviation, automotive electronics, and industrial equipment.
5) What are the differences between silicon capacitors and MLCCs in high-frequency scenarios?
Capacitance Density: Silicon capacitors achieve higher capacitance per unit area through 3D nanostructures, which is especially suitable for ultra-thin packages.
ESL/ESR: The equivalent series inductance and resistance of silicon capacitors are significantly lower than those of MLCCs, which can simplify filter circuit design.
6) What should be noted when using silicon capacitors?
Package Compatibility: The welding or wire bonding package form needs to be selected according to the application scenario.
Voltage Matching: The voltage resistance level of the dielectric material needs to be consistent with the circuit requirements.