Hexagonal Wurtzite Type Epitaxial Layer with a Low Alkali-Metal Concentration

Tech ID: 23657 / UC Case 2008-658-0

Brief Description

A method to produce hexagonal würtzite type epitaxial layers possessing low alkali-metal concentration.

Background

A high-quality substrate is essential for fabrication of GaN devices, which has led to various approaches for growing GaN single crystal substrates. In most approaches, alkali-metals are added to the growth system, causing the grown GaN crystals to contain high concentrations of alkali-metals.  This high concentration of alkali metals severely increases the likelihood that alkali-metals will diffuse into the epitaxial layers, having a negative impact on the electrical properties and performance of devices.

 

Description

Researchers at the University of California, Santa Barbara have developed a method to produce hexagonal würtzite type epitaxial layers possessing low alkali-metal concentration. While incorporation of alkali-metals is essential to the growth process, they have a negative impact on device properties. We have found that the diffusion of alkali-metals into the epitaxial layer strongly depends on the crystal plane of the substrate and therefore can be effectively suppressed. This method produces bow-free GaN substrates containing low structural defect densities in a cost effective manner, allowing manufacturers of both devices and substrates to benefit.

 

Advantages

  • Low alkali-metal diffusion
  • Improved device performance


Applications

  • LEDs and Laser Diodes
  • High Electron Mobility Transistors (HEMTs)
  • Power switching devices


Patent Status

Country Type Number Dated Case
United States Of America Issued Patent 8,647,967 02/11/2014 2008-658
 

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Keywords

indssl, cenIEE, indfeat

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