Development of high-efficiency and high-power vertical light emitting diodes

We provide an overview of the vertical chip technology and discuss recent improvements that have enabled (AlGaIn)N-based light-emitting diodes to further extend the range of their applications. In particular, the excellent scalability of chip size and low electric losses make related devices predestinated for use in high-power and high-luminance tasks. The evolution from standard vertical chips to the advanced chip design is described from a conceptual as well as from a performance point of view. Excellent stability data under demanding conditions are shown, which are the basis for the operation of devices in automotive applications requiring high reliability at current densities exceeding 3A/mm(2). As the vertical chip technology is not directly dependent on the substrate owing to its removal in the chip process, it is highly flexible with respect to the change of substrate materials to the very promising (111) silicon, for example. (C) 2014 The Japan Society of Applied Physics