BRUSSELS, Belgium – European research institute IMEC
and its partners in a program on gallium-nitride fabrication have produced
device quality GaN/AlGaN layers on 200-mm silicon wafers.
These first GaN devices on 200-mm diameter wafers
are an important milestone on the path to cost-effective production of power
devices in high-productivity 200-mm fabs.
Functional GaN MIS-HEMTs were processed using an
advanced MOCVD system from Applied Materials but in general with standard CMOS
Conventionally, gold is used for ohmic contacts and
gate structures in power devices, but it makes GaN processing incompatible with
conventional CMOS processing. To overcome this, imec based the ohmic contact
formation on an Au-free metallization system, and modified the Schottky gate to
a gate dielectric based gold-free metal-insulator-semiconductor (MIS)
structure. This introduction of the MISHEMT structure had the added advantage
of reducing the high leakage current of conventional HEMTs.
Power devices on 200-mm CMOS-compatible GaN-on-Si.