Lux: High-Efficiency Semiconductor Costs to Drop

Wide-band-gap semiconductor materials such as gallium nitride, or GaN, offer far higher efficiencies than traditional silicon but cost significantly more. But by 2020 GaN costs will drop enough for it to become competitive based on performance gains, according to a Lux Research report.

Bulk GaN is very expensive today, costing about $1,900 or more for a two-inch substrate, compared with $25 to $50 for a far larger six-inch silicon substrate. But GaN materials offer higher efficiencies than silicon, leading to greater energy savings in devices like power electronics, laser diodes, and light-emitting diodes (LEDs). These gains can offset cost disadvantages – the price-to-performance ratio is the key to adoption, according to Price or Performance: Bulk GaN Vies with Silicon for Value in LEDs, Power Electronics and Laser Diodes.

The future of bulk GaN is going to come down to how it faces off against silicon substrates, according to Pallavi Madakasira, Lux Research analyst and the lead author of the report. “Bulk GaN wins in laser diodes and it can become relevant in LEDs and power electronics by boosting yield and performance,” said Madakasira.

Lux Research analysts broke down the manufacturing costs for ammonothermal and hydride vapor phase epitaxy, or HVPE, processes for making bulk GaN, as well as for GaN epitaxy on both silicon and GaN substrates, and determined where the price/performance trade-off will land. They found that HVPE is the cheaper alternative.

Two-inch ammonothermal substrate costs will fall by more than 60 percent to $730/substrate in 2020. While four-inch HVPE substrate costs will fall by 40 percent to $1,340/substrate in 2020, the larger size makes it the more economical choice, the report says.

Bulk GaN can overcome high cost by boosting performance in terms of lumen  output in LEDs or volt-amp capacity in power electronics, by allowing the use of smaller dies and providing higher yields. In LEDs, GaN can match silicon with a 380 percent relative performance – an “ambitious but realistic” goal, according to Lux. For power electronics, performance at 360 percent of devices on silicon makes bulk GaN “a winner,” according to Lux.

In July, researchers at the University of Arizona said they had developed semiconductor manufacturing process that cuts water and energy use by 30 percent. The university’s SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing’s sensor-based approach delivers the savings in the rinse and cleaning of wafer semiconductor materials by monitoring the wafer’s surface in real-time to curb excessive use of resources.