"The industry must move to large diameter wafers to reduce costs, but older sapphire technology has significant limitations moving in that direction," said Hap Hewes, ARC Energy's senior vice president. "That's exactly why we developed CHES technology: to reduce costs for large diameter LED sapphire wafers."
Today's high-brightness LED (HB-LED) industry is searching for dramatic cost savings to reduce the price of solid state lighting to enable mass adoption by the general lighting market. A key component to reduce costs is widely identified as moving to large diameter substrates, similar to the move the silicon industry made over 20 years ago. "Sapphire That Scales" explains the significant advantages of moving to 150mm (6-inch) and 200mm (8-inch) substrates. A single MOCVD run simulated using 150mm wafers results in 55% more LED chips. With 200mm wafers the improvement increases to 77% more LED chips over using standard 50mm wafers.
Although large diameter substrates have significant benefits, older sapphire growth technology has very low material utilization when growing these substrates. In addition, due to a non-uniform growth time signature, older sapphire growth technologies result in larger and uneven bowing (warp) during epitaxy process in a MOCVD reactor. This reduces LED chip yield and requires expensive workarounds.
CHES technology was designed to overcome the drawbacks of older sapphire technologies at large diameters. CHES provides a high material utilization on c-axis and with low defect levels. In addition, growing along the c-axis produces wafers with a single time signature which can result in less bow and warp during epitaxy in the MOCVD reactor. CHES furnaces grow near net shape c-axis boules for 150mm and 200mm cores in production today. This makes CHES furnaces the leading choice for the future of HB-LED production on large diameter sapphire substrates.