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Modeling, Fabrication and Test Results of a MOS Controlled
Thyristor - MCT - with High Controllable Current Density.
Evgeny Chernyavskiy1, Vladimir Popov1, Bert Vermeire2
1 Institute
2
of Semiconductor Physics SB,
RAS, Lavrentev pr. 13,
Novosibirsk, Russia.
Ridgetop Group Inc.,
6595 N. Oracle Road,
Tucson AZ, USA.
MCT Multi-cell Structure and Equivalent Circuit:
PMOS channel resistance:
Emitter cells: 144,000
Emitter cell size: 10 x 10 mm
MCT current limitation:
Active area: 0.33 cm2
Breakdown Voltage: 2.5 kV
2-D p-i-n Diode Model:
The 2D p-i-n diode model with
N+
emitter
shunted
by
PMOSFET
is
physically
equivalent to the MCT for
realistic current densities.
The
current
density
modulation coefficient (M)
decreases with increasing
current density.
On-state
current
density
measurements match the p-i-n
diode model simulations when
carrier lifetime is 25 ms (squares)
and when it is 3.5 ms (dots).
Jmcc criterion:
n:
electron concentration
Na: acceptor doping profile
in the P base
Ja:
current density before
modulation
The electron density in the center
of the N emitter with gate voltage
Ug = -15 V becomes larger than
the accepter doping when Ja = 132
A/cm2
New criterion for evaluation of the
maximum controllable current
density in an MCT: If the electron
concentration is lower than the
acceptor concentration (n < Na) at
when the negative gate voltage is
applied, then current density is
controllable.
We believe this to be due to
charge compensation.
The experimental maximum
controllable current density
with a lifetime of 25 ms is 100
A/cm2 (compared to the
simulated value of 132 A/cm2).
The MCT was irradiated with
2 MeV electrons. The carrier
lifetime is reduced to 3.5 ms.
The maximum controllable
current density increased to
150 A/cm2.
Conclusions:
•
•
A 2D physical equivalent static
model of the MCT using p-i-n diode
equivalent allows the maximum
controllable current density to be
determined
from
the
carrier
concentrations.
An MCT with high controllable
current density (150 A/cm2) was
manufactured
and
accurately
modeled using the static model.