What Are Gallium Doped Substrates?

university wafer substrates

Gallium Doped Silicon Wafers

A PhD candidate requested a quote for the following.

I am looking for a solar grade P-type Boron Substrate silicon wafer for my project research. I tried to find it over the internet but can't find the desired wafer. Please let me know if its available. If its not please share details if you have any idea about its availability elsewhere. Thanks a lot. Following are my requirements Quantity=5 Diameter=4inch Thickness=500 microns Boron/Gallium doped SSP

Reference #273980 for specs and pricing.

Get Your Quote FAST! Or, Buy Online and Start Researching Today!





 

 

What are Gallium Doped Substrates and What Are Their Applications?

Gallium-doped substrates are semiconductor wafers in which gallium (Ga) is intentionally introduced as a dopant during the crystal growth process. Doping involves adding a small concentration of impurity atoms to the base material (typically silicon or germanium) to modify its electrical and physical properties.

Key Characteristics of Gallium Doping:

  • P-type conductivity: Gallium is a Group III element in the periodic table. When doped into silicon (a Group IV element), it creates an electron deficiency (holes), resulting in p-type semiconducting behavior.
  • High thermal stability: Gallium-doped silicon exhibits stability at high temperatures compared to other p-type dopants like boron.
  • Low diffusion coefficient: Gallium has a lower diffusion rate in silicon than boron, making it ideal for applications requiring well-defined doping profiles.
  • Deep-level doping: Gallium can introduce deeper acceptor levels in some semiconductors compared to other dopants.

Applications of Gallium-Doped Substrates:

1. High-Power Electronics:

  • Used in power devices and high-voltage applications where low leakage current and high thermal stability are crucial.
  • Preferred in power MOSFETs, IGBTs, and thyristors.

2. Radiation-Hardened Devices:

  • Gallium-doped silicon is less susceptible to radiation-induced defects, making it suitable for space applications, nuclear environments, and military electronics.

3. High-Temperature Applications:

  • Because gallium is thermally stable, gallium-doped substrates are used in sensors, diodes, and transistors that operate in elevated temperature environments.

4. Optoelectronics:

5. Advanced CMOS Technology:

  • In niche CMOS processes, gallium doping can be used to enhance carrier mobility and device performance in specific designs.

6. Photovoltaics:

  • Some specialized solar cells (e.g., space-grade photovoltaics) may utilize gallium doping for enhanced efficiency and radiation resistance.

7. Neutron Transmutation Doping (NTD):

  • Gallium is sometimes introduced in NTD silicon, where precise resistivity control is required, such as in high-precision resistors and metrology devices.

Comparison with Other P-type Dopants:

Dopant Diffusion Rate in Si Thermal Stability Radiation Resistance Common Applications
Boron High Moderate Low General ICs, MEMS
Gallium Low High High Power devices, Space
Aluminum Moderate Low Moderate High-power diodes
Indium Very Low Very High High High-temperature devices

Summary:

Gallium-doped substrates are prized in high-power electronics, radiation-hardened environments, and high-temperature applications due to their thermal stability, low diffusion coefficient, and radiation resistance. They are less common than boron-doped substrates but are critical for specialized applications requiring these enhanced properties.