Bulk Products

Bulk Gallium Nitride

Semiconductor epitaxy is best performed on native substrates in order to minimize interface effects and defect formation. Gallium nitride epitaxy on Kyma GaN substrates greatly improves a number of important device properties of subsequent GaN epitaxy when compared with heteroepitaxial GaN on SiC, sapphire, or silicon. The benefits in lattice constant mismatch, dislocation density and thermal conductivity can be seen in the table below.

Bulk GaN vs Non-native Substrates
 GaN on Bulk GaN†GaN on SiCGaN on sapphireGaN on Silicon
Lattice Constant Mismatch 0% 3.5% mismatch 14% mismatch 17% mismatch
Dislocation Density 104 - 106 / cm2 1 x 109 / cm2 5 x 109 / cm2 1 x 1011 / cm2
Thermal Conductivity 2.5 W/cm-K 1.3 W/cm-K 1.2 W/cm-K 1.0 W/cm-K
†Kyma does not currently sell epitaxy on Bulk GaN. The data listed here is from a wide variety of customer reported epitaxy results.

 

Kyma's high purity GaN substrate allows GaN-based device manufacturers to eliminate interlayers, processing steps, and improve device quality over those grown on any other substrate. Detailed product descriptions and specification sheets are listed below.

All substrates have a typical dislocation density of 5x106and epi-ready surface finish.

For more information concerning bulk GaN substrate products follow the links below:

 

High Purity Polycrystaline Galliumn Nitride

Kyma's polycrystalline GaN (Poly GaN) is useful for applications that require higher purity and/or lower surface area than traditional GaN powder provides. We are able to manufacture polycrystalline GaN in solid discs, squares or as pellets, depending on your preferred form factor. Customers have reported improved results across a variety of GaN growth methods, including PLD, sputtering, ammonothermal, and solution growth when comparing our high purity material to traditional feedstock materials available elsewhere.

For more information about high purity Poly GaN products follow the link below:

Specification Sheet Characterization Methods

Characterization of products as shown in our specification sheets is completed using the following methods:

  • Wafer thickness, Bow and TTV are determined by a Sigmatech thickness mapper for round substrates. Square substrates are measured manually at predetermined points on the wafers.

  • Wafer orientation is determined by x-ray diffraction

  • Conductivity is determined by Lehighton (n-type, semi-insulating) and/or Corema measurements (semi-insulating) and/or Hall measurements for our boule recipes, but are not made on all wafers shipped.

  • Dislocation density is determined via etch pit density measurements followed by AFM and/or micro-cathodoluminescence (Micro-CL), but are not made on all wafers shipped.

  • Macro defects are on the surface of the wafer and are counted by visual inspection.

  • Surface roughness information is determined by atomic force microscopy (AFM) for the front surface finish. The typical image size for the measurement is 20x20 microns.