WBG substrates for devices, progress and trends (SiC to III-nitrides comparison)

Resent enormous growth of LED market has left fare behind the progress in the development of native substrates that is still in the very early stage from the industrial production standpoint. Current approach using sapphire based substrate technology seems to dominate for the current cycle of the industry development. This trend is not only defined by the immaturity of native substrates technology but is also driven by the cost-to-performance trade-off. The volume of investments made in current sapphire based LED technology will not allow the native substrates to replace sapphire until the return on this investment will be reached. Alternatively the performance or cost of the native substrate based LEDs will make it technically and financially more attractive to LED manufacturers or create new market sectors for native III-nitride substrates. In contrast to SiC market in the early 90^th there is no immediate need of native substrates for supporting the explosion of nitride based device market. High frequency high power devices based WBG materials will be using hetero-substrates as substrates are not currently performance limiting element of the technology. Even at current levels of defect densities in nitride materials grown on relatively chip foreign substrates assures the commercially viable range of applications. This range is defined by applications where nitride devices supersede traditional materials or do not have any existing incumbent materials. The availability of Silicon based large area hetero substrate technology for III-N based High Frequency-High power devices creates another cost stopper for native substrates applications in this area.