ALLOS Semiconductors of Dresden, Germany reported that it established the firm’s epiwafer growth processes using a customer’s Aixtron G5 and Veeco K465i reactors. Therefore, in addition to providing the desired gallium nitride on silicon (GaN-on-Si) epiwafers, the project gave the company a unique performance and cost comparison between Aixtron’s G5 system and Veeco’s K465i reactor.
The company notes it has achieved very low leakage currents and superior crystal quality that mass-market adoption of GaN-on-Si for power electronic applications requires. ALLOS says its technology has attained the low vertical leakage current of less than 0.1 µA/mm² at 600 V. At the same time the technology employs optimal growth conditions for reaching high crystal quality without the need for carbon or other dopants to isolate the GaN.
While an increasingly common technique, such carbon doping to increase isolation results in crystal quality degradation. Like other experts, ALLOS expects that insufficient crystal quality can negatively impact performance and quality. Not using doping also avoids potential IP conflicts related to doping.
ALLOS says that customers using its technology can produce cost-efficient GaN-on-Si epiwafers of up to 200 mm diameter, which meet the SEMI-standard specification for thickness and bow, show excellent electrical performance, and prove very reliable in device making.
The firm also says it recently transferred and adapted its latest technology generation for a power electronics customer. The project required developing customized interlayer and superlattice based epi structures with up to 7 µm total thickness for 150 and 200 mm diameter wafers. Additionally, project establishing the epi process in both the Aixtron G5 and Veeco K465i reactors that the customer used for GaN-on-Si fabrication. The customer found that the overall differences in the results between the two reactors to be small, and each showed merits and demerits.