Self-Aligned InGaAs Channel MOS-HEMTs for High Frequency Applications

A gate to link self-aligned,
$L_{g}=20$
nm, In
0.80
Ga
0
.
20
As MOS-HEMT exhibiting
$f_{t}=525$
GHz and
$f_{max}=709$
GHz at
$V_{DS} =1.00\ \mathrm{V},\ V_{GS}=0.20\ \mathrm{V}$
, and
$I_{DS}=0.624\ \text{mA}/\mu \mathrm{m}$
is reported. Also, a self-aligned,
$L_{g}=36$
nm, In
0.80
Ga
0
.
20
As MOS-HEMT exhibiting
$f_{t}=485$
GHz and
$f_{max} > 1$
THz, at
$V_{DS}=0.9\ \mathrm{V}, V_{GS}=0.20\ \mathrm{V}$
, and
$I_{DS}=0.528\ \text{mA}/\mu \mathrm{m}$
is reported.
$f_{t} =525$
GHz and
$f_{max}$
exceeding 1 THz are both the highest report for III-V MOSFETs. The typical T-gate formation via bilayer resist is replaced with a V-gate via a regrown, sacrificial InP support that is later etched in dilute HCl, and the traditional thick topside modulation doped link is replaced by a thin Si:In
0.53
Ga
0.47
As
$(4.0\times 10^{19}\ \text{cm}^{-3})$
layer. An Al
x
O
y
N
z
/ ZrO
2
high-k gate dielectric is used with a 6.0 nm In
0.80
Ga
0.20
As channel. At 16 nm
$L_{\mathrm{g}}$
, low
$g_{ds, e}=0.13\ \text{mS}/\mu \mathrm{m}$
at
$V_{DS}=1.00\ \mathrm{V},\ V_{GS}=0.20\ \mathrm{V}$
was achieved. At
$L_{g}=1000$
nm,
$V_{DS}=0.10\ \mathrm{V},SS_{min}=82\ \text{mV}/\text{dec}$
is observed. High frequency performance of the present device is limited by
$g_{m, e} < 2\ \text{mS}/\mu \mathrm{m}$
.