The G-Stack™ material solution

Exagan’s proprietary G-Stack material technology allows the production of thick, high-quality GaN films on Silicon for large-scale wafer manufacturing.

Using standard and state-of-the-art epitaxial equipment from leading MOCVD vendors, Exagan’s GaN-on-silicon process allows tight control of wafer flatness as well as the material’s crystalline properties, such as defects, impurities and thickness, for producing high-breakdown-voltage and low-leakage devices.

Exagan G-Stack technology
Exagan G-Stack technology

GaN and silicon have very different crystal-lattice parameters and thermal expansion coefficients, which make it difficult to combine them. Typically grown at 1,000° C to 1,100° C, GaN films deposited on silicon are stretched and put under tension during the cool down phase, often causing them to crack before reaching room temperature.

Overcoming GaN-on-Silicon's technological hurdles

Exagan’s G-Stack epitaxial technology creates a unique sequence of GaN -based materials that is stacked as buffer to create high-quality GaN material. Strain-management layers are then inserted in the GaN material, allowing GaN crystal relaxation and avoiding the cracking phenomena.

With its unique G-Stack technology backed by more than 10 years of development, Exagan provides a material-stack engineering solution with:

  • Perfect control of stress balance within the GaN epi structure,
  • GaN crystal relaxation to limit the strain in the material (due to lattice mismatching) when growing thick films,
  • Freedom to optimize material structures, quality and electrical properties.

G-Stack technology offers a major advantage compared to conventional methods for growing thick and high-quality materials, achieving up to twice the layer thicknesses. As a consequence, G-FET™ devices are developed using 200-mm wafers that are crack-free and extremely flat for manufacturing in standard silicon fabs. An extensive range of GaN layers is offered to meet targeted device requirements in terms of breakdown voltage, vertical leakage and temperature operation.

This proprietary technology is the most effective solution to achieve the ultimate balance between high-quality, crack-free material, stress management and flat 200-mm wafers, enabling standardized manufacturing of GaN-on-silicon devices for applications up to 1,200 volts.

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