Dielectric ceramics and substrates are electrical insulators with dielectric strength, dielectric constant and loss tangent values tailored for specific device or circuit applications.

In capacitor applications, ceramics with a high dielectric constant are used to increase the charge that can be stored. In microelectronic circuits, low dielectric constant or low-k materials are sought to reduce inductive crosstalk and noise generation in the circuit.

In high voltage insulator applications, high electrical resistivity (ohm-cm) and high dielectric strength (KV per meter) is required.

Dielectric Ceramic Parameters

• Dielectric strength
• Dielectric constant (relative permittivity)
• Loss tangent (tan)
• Electrical resistivity
• Operating frequency

Dielectric strength is the maximum voltage field that the ceramic or material can withstand before electrical breakdown occurs. The dielectric constant is the relative permittivity of a material compared to a vacuum or free space.

In dielectric materials, the loss tangent or loss coefficient is the ratio of the imaginary or loss permittivity to the real permittivity of a material.

Resistivity is the longitudinal electrical resistance (ohm-cm) of a uniform rod of unit length and unit cross-sectional area. Operating frequency is the frequency range that the material is capable of operating within while providing acceptable performance and/or without excessive power losses.

Dielectric Ceramic Materials

• Alumina

• Aluminum nitride
• Aluminum silicate or sillimanite
• Barium neodymium titanate
• Barium strontium titanate (BST)
• Barium tantalate
• Barium titanate (BT)
• Beryllia
• Boron nitride
• Calcium titanate
• Calcium magnesium titanate (CMT)
• Glass ceramic
• Cordierite / magnesium aluminum silicate
• Forsterite / magnesium silicate
• Lead magnesium niobate (PMN)
• Lead zinc niobate (PZN)
• Lithium niobate (LN)
• Magnesium silicate
• Magnesium titanate
• Niobate or niobium oxide
• Porcelain
• Quartz
• Sapphire
• Strontium titanate
• Silica or silicate
• Steatite
• Tantalate or tantalum oxide
• Titania or titanate
• Zircon
• Zirconia or zircoate
• Zirconium tin titanate

The dielectric ceramic can be provided as a piezoelectric or relaxor ceramic, which is a dielectric ceramic with piezoelectric or electrostrictive characteristics.

Product Forms and Types

• Bar
• Disc
• Plate or slab
• Powder or grain
• Precursor
• Ring
• Rod
• Tube or cylinder
• Sputtering target
• Wafer or substrate
• Custom or application specific forms

Features

• Stack or multilayer composite
• Electrical or high voltage
• Glaze or protective coating
• Metallized or electrode
• Modified or doped
• Microwave or high frequency

• Single crystal construction

 Metal Layers

• Silver
• Gold
• Gold-tin alloy
• Copper
• Nickel
• Tantalum nitride
• Titanium-tungsten

The metallization method for dielectric ceramics and substrates can be electroplated, fired on or thick film, patterned circuits or vias, evaporated thin film, or sputtered thin film.

Standards

BS EN 60384-21 - Fixed capacitors for use in electronic equipment part 21: sectional specification - fixed surface mount multilayer capacitors of ceramic dielectric, class 1.

BS DD IEC/TS 61994-4-2 - Piezoelectric, dielectric and electrostatic devices and associatedmaterials for frequency control, selection and detection - glossary part 4-2: piezoelectric and dielectric materials - piezoelectric ceramics.

DSCC-DWG-97006 -  Capacitors, fixed, ceramic dielectric, non-hermetically sealed, feedthrough.

EIA IS 36 - Chip capacitors, multi-layer (ceramic dielectric).

References

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