April 4, 2025
Shop NowA material’s electrical properties play a significant role during silicon wafer manufacturing. Band gap energy, carrier mobility, and breakdown voltage are all essential concepts that help understand how a material will perform in a specific situation and whether the results will be satisfying or subpar.
Therefore, understanding these concepts is crucial to purchasing the right semiconductor material for your project. To help you, we created this guide, breaking down the wafer’s electrical properties in detail.
Several important electrical characteristics determine a semiconductor material's suitability for a project. Some of the most important ones are:
Bandgap energy is a fundamental concept in solid-state physics and semiconductor manufacturing. It describes the range of energies in a solid devoid of electronic states. This energy gap is crucial because it influences how much energy is needed to excite an electron into conduction, which influences the material's electrical conductivity.
To be precise, it is the energy differential between the bottom of the conduction band and the top of the valence band. In semiconductors, electrons are confined to specific energy bands.
The valence band is the highest range of electron energies where electrons are normally present at absolute zero temperature. In contrast, the conduction band is the range of electron energies higher than the valence band, where electrons are free to move and conduct electricity.
When an electron gains enough energy to jump to the conduction band, it leaves behind a hole in the valence band. The electron and the hole can move freely within the crystal lattice, contributing to electrical conductivity.
The size of the band gap varies among different materials. It’s a key factor in determining whether a material is an insulator, semiconductor, or conductor.
Furthermore, semiconductors can be classified by their type of band gap.
In a direct band gap semiconductor, the momentum of the electrons in the valence band and the conduction band is the same, allowing electrons to be directly excited by photons. This makes direct band gap materials, such as GaAs (Gallium Arsenide) and InP (Indium Phosphate), more efficient for light-emitting applications like LEDs and laser diodes.
In contrast, indirect band gap semiconductors require a phonon (a quantum of vibrational energy) to assist in the transition. For that reason, elements like Si (Silicon), Ge (Germanium), and SiC (Silicon Carbide) are less efficient for light emission but still useful in applications like photovoltaics.
Narrow bandgap semiconductors are suitable for low-voltage, high-speed devices. A narrow bandgap means the energy difference between the conduction and valence bands is small (usually < 1.5 eV). They’re more sensitive to temperature and light and have higher intrinsic carrier concentrations.
On the other hand, wide bandgap materials have a larger energy difference (typically > 2 eV). They excel in high-power, high-temperature environments (like power electronics). They’re also ideal for high-power, high-temperature, and high-frequency applications.
Carrier mobility in a semiconductor refers to how easily charge carriers (electrons or holes) can move through the material when an electric field is applied. Precisely, it states how quickly electrons (μₑ) or holes (μₕ) can move through the material when an electric field is applied.
This electrical property is fundamental because it affects how fast and efficiently a device operates. High mobility equals faster switching speeds and lower power consumption. It also affects how much current can flow through a device for a given voltage.
Higher mobility means charge carriers respond faster, resulting in faster transistors, quicker switching, and lower power losses. Therefore, this property is critical for high-speed transistors like RF or logic circuits.
Additionally, good mobility allows for efficient charge separation and collection in solar cells, photodetectors, and LEDs.
The intrinsic carrier concentration is the number of charge carriers (or electrons) naturally available in an undoped semiconductor. The number of carriers depends on the material's band gap and temperature.
Intrinsic carrier concentration sets the “default” level of conductivity. Thanks to the few naturally moving charges, even if you don’t add anything to the material, it can still carry a small electric current.
Some materials naturally have many moving charges (like Germanium), while others have very few (like Gallium Nitride). This helps decide the best material for solar panels, computer chips, or power converters.
Lower intrinsic carrier concentration also leads to better control when doping the material. Engineers often add other atoms to the material (doping) to increase moving charges. But they need to know the starting point—and that’s what the intrinsic carrier concentration tells them.
The dielectric constant, also called relative permittivity, tells us how well a material stores electrical energy in an electric field. It measures how well an applied electric field can penetrate a dielectric medium compared to a vacuum. It is measured in farads per meter (F/m).
A high dielectric constant in electronics means the material is better at holding electrical energy between two charged plates, like in a capacitor or a transistor.
The dielectric constant affects the capacitance between semiconductor regions and the ability to store electrical energy. Materials with a suitable dielectric constant help control signals without allowing them to leak or interfere with each other.
It also determines how well a material insulates different regions in a chip. Too high may cause unwanted charging effects, and too low may cause signals to behave improperly. Moreover, it influences speed and signal integrity in integrated circuits.
High dielectric constant materials are good for capacitive sensors or gate insulators in MOSFETs.
Breakdown voltage is the maximum voltage a semiconductor device can handle before it loses control and starts conducting electricity in a dangerous or unintended way. It’s a key measure for power electronics and isolation components.
When the voltage across a semiconductor part gets too high, the electric field becomes so strong that it rips electrons away from atoms. This triggers a chain reaction: suddenly, tons of current flow. If the device wasn’t designed for this, it could overheat, burn out, or even explode.
Materials with high breakdown voltages (like SiC) are chosen for high-voltage power converters and electric vehicles.
Resistivity measures how strongly a material resists the flow of electricity. Think of it like the friction electricity feels as it moves through a material.
In semiconductors, resistivity can change dramatically based on temperature, how the material is made, and whether it’s been doped (had special atoms added). Resistivity (ρ, the Greek letter rho) is measured in ohm-centimeters (Ω·cm).
Balancing low resistivity in conductive paths and high resistivity in insulating regions within chips and sensors is crucial. Unlike metals (which have mostly constant resistivity), semiconductors are dynamic:
Thermal conductivity is a measure of how well a material can carry heat.
It’s measured in watts per meter-kelvin (W/m·K)—basically, how many watts of heat energy can move through one meter of material per degree of temperature difference.
Heat dissipation is critical in high-performance and high-power applications, which require materials that can handle high voltage and heat. That’s where materials like SiC and GaN shine.
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Semiconductors are unique materials that have become essential to today’s electronics. Because each material offers unique properties, engineers must determine which suits their project’s requirements and performance ideals better.
Here at Wafer World, we offer various semiconductor materials to help you. Contact us today for more information!
