MOCVD Growth of High Quality InGaAs HEMT Layers on Large Scale Si Wafers for Heterogeneous Integration With Si CMOS

We report on the growth of In
_0.30
Ga
_0.70
As channel high electron mobility transistor (HEMT) epi-layers on a 200-mm Si substrate by metal-organic-chemical-vapor-deposition. The HEMT layers were grown on the Si substrate by using a ~3-
${\mu }\text{m}$
thick epitaxial buffer composing of a Ge layer, a GaAs layer, and a compositionally graded and strain relaxed InAlAs layer. The optimized epitaxy has a threading dislocation density of less than
$2 {\times } 10^{{7}}$
cm
⁻²
and a root mean square surface roughness of ~6.7 nm. The device active layers include a
${ {\delta } }$
-doped InAlAs bottom barrier, a ~15-nm thick InGaAs channel, a ~8-nm InGaP top barrier layer and a heavily doped InGaAs contact layer. MOSHEMTs with channel length down to 130 nm were fabricated. The devices achieve a peak transconductance of
${\sim }450 ~{\mu }\text{S}/ {\mu }\text{m}$
at
${V} _{ D}$
of 0.5 V. The peak effective mobility (
${\mu }_{\text {eff}}$
) in a device with a channel length of 20
$ {\mu }\text{m}$
device channel was ~3700 cm
²
/
$\text{V} {\cdot }\text{s}$
.