A provider of rare-earth-oxide (REO) made silicon substrates for delivering less expensive and superior performance epitaxy, Translucent, has developed an in house GaN-on-Si wafer template with integrated DBR mirrors for enhancing the growth of less expensive LEDs.
Translucent produces wafers with a diameter of 100 mm that features high reflective property utilizing a lattice-engineered REO substance that is made to grow epitaxially on a silicon (111) substrate. This material is covered by a layer of GaN that can provide support for nitrite epitaxy to enhance the development of LED materials. This lattice-engineered REO material can be used to lessen the strain that occurs during the GaN growth process. Besides, the REO materials provide high reflection mirrors that are embedded in the designed silicon substrates. This new technology enables the growth of LEDs on wafers with huge diameter.
Translucent’s silicon system, Mirrored Si, lessens the requirement to utilize handle wafers and the removal of the substrate during processing. This system enables LEDs to directly grow onto the GaN-on-Si template with an embedded DBR mirror.
The DBR mirror is covered with a layer of in house patented REO, which enables GaN to cover the template, thereby reducing the need for substrate removal. It was found that with LED grown on thin layers of lattice-engineered REO material that emit a wavelength of about 450 nm, the reflectivity of the mirror can go beyond 98%. Molecular beam epitaxy (MBE) reactors were employed to grow the LEDs at Translucent’s division. Translucent is presently trying to improve its integrated silicon mirror technology for commercial applications utilizing wafers with 150 mm and 200 mm diameter.