19 November 2010

SEI unveils first 6” GaN substrates for white LEDs

Tokyo-based Sumitomo Electric Industries Ltd (SEI) has developed what it claims are the first 6-inch diameter gallium nitride (GaN) substrates to be used for white light-emitting diodes.

Previously, Sumitomo Electric was first to produce 2”-diameter GaN substrates for blue-violet lasers, which enabled production of the first Blu-ray DVD players.

Picture: SEI’s 2–6” GaN substrates.

The white LED market has been growing rapidly using 2–4”-diameter sapphire substrates. As an alternative to sapphire, Sumitomo Electric began large-scale production of 2”-diameter GaN substrates designed for use in white LEDs. It has also been developing larger-diameter GaN substrates.

SEI says that GaN substrates allow better thermal dispersion and other properties that can enable LED makers to reduce chip sizes and increase output power. It also believes that GaN substrates will be used for power devices because of their excellent thermal conductivity and electric responsiveness as well as the breakdown voltage of devices made using these materials.

The front face of the new 6” GaN substrates is a polarized c-plane, which is the plane that is generally used for white LEDs and blue-violet or blue lasers (although the polarization decreases light-emitting efficiency in the green region, compared with non-polar or semi-polar GaN crystal orientations).

SEI says that it has ongoing development efforts to bring its 6” GaN substrate into large-scale production, and it expects that the material will find wide-spread use for both white LEDs and power devices.

Tags: SEI GaN substrates White LEDs

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