
88 Gallium Nitride (GaN): Physics, Devices, and Technology
ohmic contact is due to the formation of a low-metal-work-function Ti
x
Si
y
alloy at
the metal–semiconductor interface as well as the intermixing of Ti
x
Si
y
with the
bottom Ta metal layer. The formation of the alloy was conrmed by powder X-ray
diffraction, HR-TEM, and energy-dispersive X-ray spectroscopy analysis [68]. The
developed low R
c
non-gold ohmic contact to the conventional undoped AlGaN/GaN
HEMT structure is shown to be promising for the mass production of low-cost GaN
HEMTs on Si substrates in well-established silicon CMOS fabrication lines.
After the ohmic contact formation on ...