The goal of every HBLED manufacturer is more light for less money. With strong competition and numerous technology hurdles it is vital that all manufacturing steps are pushed.Mark Dineen, Product Manager (HBLED) at Oxford Instruments Plasma Technology discusses how optimised plasma etching offers several ways to improve device output and reduce costs providing a double windfall.
I
have never thought of myself as a veteran, but with over 15 years working on HBLEDs I guess that makes me one. When I first started out, plasma etching was used as a tool to etch down through the p-type layer into the n-type in order to make a contact. Since then we have seen several new applications that mean plasma etching is even more important.
Patterned Sapphire Substrates Sapphire, at the moment, is still the substrate of choice for growing HBLED structures. However, there are two problems with growing on Sapphire: it is not a perfect lattice match and light extraction is reduced by having two parallel reflecting surfaces. In order to improve both these issues from 2005 onwards companies have been