High Capacitance Density MOS Capacitors 30V Single Layer 1000 pF Capacitor Chip For RF Microwave Circuits

High Capacitance Density MOS Capacitor HACC102S30V500 1000pF 30V Single Layer Chip for RF Microwave Circuits

HACC102S30V500 High Capacitance Density MOS Capacitor

The HACC102S30V500 is a single-layer metal-oxide-semiconductor (MOS) capacitor fabricated on a high-resistivity silicon substrate with thermally grown silicon dioxide (SiO₂) as the dielectric layer. Nominal capacitance is 1000pF (1nF) at a rated working voltage of 30V DC. The chip measures 0.50mm * 0.50mm * 0.15mm, with 2.5µm minimum gold top metallization and 1.0µm minimum gold backside metallization. It is designed for RF and microwave circuits where compact size, low insertion loss, and predictable thermal behavior are primary design considerations.

MOS Capacitor Advantages vs. MLCC

At comparable capacitance values, single-layer MOS capacitors offer distinct performance benefits over multilayer ceramic capacitors (MLCCs) in high-frequency applications:

• Lower series inductance: The single-layer construction eliminates the internal electrode stack of an MLCC. Typical equivalent series inductance (ESL) is under 0.05nH, giving the HACC102S30V500 a self-resonant frequency (SRF) above 6GHz and a usable bandwidth extending well into the X-band.
• Stable capacitance vs. DC bias: Unlike Class II ceramic dielectrics (X7R, X5R) that can lose over 50% of rated capacitance at rated voltage, the SiO₂ dielectric in the HACC102S30V500 maintains rated capacitance across the full 0-30V DC bias range.
• Well-defined temperature coefficient: The SiO₂ dielectric exhibits a temperature coefficient of capacitance (TCC) of approximately +35ppm/°C, nearly linear across -55°C to +125°C. This allows designers to apply predictable temperature compensation, for example by pairing with a negative-TCC inductor in oscillator tank circuits.
• Low dielectric absorption: Dielectric absorption is typically below 0.1%, reducing memory effects in sample-and-hold stages and precision integrators.

Key Features

• High Capacitance Density — 500nF/mm²: This density level enables compact impedance matching networks and on-chip bypass structures that would otherwise require significantly larger distributed-element geometries or multiple parallel discrete components.
• Ultra-Small 0.50mm * 0.50mm Footprint: The 20mil * 20mil chip size is suited for high-density RF front-end modules, multi-chip assemblies, and phased-array beamformer layouts where per-element real estate is limited.
• High Q Factor: Q exceeds 2000 at 1MHz and remains above 200 at 1GHz. Low ESR (typically under 0.1Ω at 1GHz) minimizes I²R loss in power amplifier bypass and DC-blocking applications.
• 300nm Thermal SiO₂ Dielectric: Grown directly on the silicon substrate, the thermal oxide provides a clean, defect-minimized dielectric interface that underpins the capacitor's low leakage and stable TCC.
• Gold Metallization for Wire Bonding: 2.5µm minimum gold top electrode supports thermosonic gold ball bonding (25µm wire, 120-150°C stage temperature, >6g pull strength typical) and ultrasonic aluminum wedge bonding (25µm wire, room temperature). Backside gold enables eutectic AuSn die attach or conductive epoxy mounting.
• ESD Sensitivity: Class 0 HBM per JESD22-A114. Standard ESD-safe handling procedures apply during assembly.

Application Design Notes

Impedance Matching Networks: With ESR < 0.1Ω at 1GHz and Q > 200, the HACC102S30V500 performs well as the capacitor element in L-section, T-section, and Pi-network matching topologies from 100MHz to 10GHz. When modeling the network, add approximately 0.05nH per 25µm bond wire for series inductance estimation.

DC Blocking: Rated at 30V DC with leakage under 10nA at 25°C, the capacitor provides effective DC isolation in amplifier bias injection circuits. Dielectric strength exceeds 100V DC (1-minute test at 25°C), giving ample headroom for most RF signal chain voltages.

Bypass and Decoupling: For effective supply decoupling above 1GHz, mount the capacitor as close as practical to the active device pad, using the minimum bond wire length or a short microstrip trace to preserve the low-impedance path to ground.

VCO and Filter Design: The +35ppm/°C TCC can be compensated with a negative-TCC inductor element to achieve net temperature drift approaching zero over the -55°C to +125°C range.

Electrical Specifications (T = 25°C unless noted)

Typical Applications

• RF power amplifier impedance matching and DC blocking
• Microwave filter, coupler, and hybrid coupler designs
• High-frequency bypass and power supply decoupling
• VCO tank circuits and resonator networks
• Medical device RF subsystems (MRI coil electronics, RF ablation generators)
• 5G small-cell and backhaul radio front-ends
• Test and measurement instrumentation (VNA calibration standards, probe cards)
• Industrial RF heating and plasma excitation equipment

Assembly and Handling

Chips are shipped in conductive waffle packs or gel-paks. Handle with ESD-safe tweezers or vacuum pickup tools. Recommended die attach methods: eutectic AuSn solder (320°C peak reflow) or silver-filled conductive epoxy (cure per manufacturer profile). Wire bonding: 25µm Au wire with thermosonic ball bonding, 120-150°C stage temperature; or 25µm Al wire with ultrasonic wedge bonding at room temperature. Store unused devices in a dry nitrogen cabinet (<10% RH) or vacuum-sealed moisture barrier bag.

Contact us to request S-parameter data (1-20GHz), reliability qualification reports, or application-specific design support.