Aluminum Nitride (AlN) Templates

In the field of nitride semiconductors, an “AlN template” refers to a composite substrate which includes a thin layer of AlN deposited epitaxially on a foreign substrate such as sapphire or silicon carbide. Kyma’s AlN templates are built on sapphire and are available from 2" to 150mm in diameter.

Kyma AlN templates are used to provide a low cost alternative to 2-step nitride nucleation processes. Kyma uses these templates for all of our GaN epitaxy, on all substrate types. There are a number of benefits that customers realize from these templates:

• PVD has excellent scalability which results in lower cost of ownership when ramping production

• Many LED customers report:

  • Better wavelength uniformity

  • Higher LED brightness

  • Better nucleation repeatability than low temperature MOCVD nucleation

• Advanced PVD reactor purchase is possible from Kyma (R&D tools) or from our equipment partners (production tools) to enable tech transfer of this process to your facility

Specification Sheet Characterization Methods

Characterization of AlN Templates 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 20x20µm.

• Epitaxial Film thickness for films under 5um thick is determined via Filmetrix or Wyko white light interferometers. Film thickness for films above 5um is typically determined by weight.