Power Bipolar Transistor and
Power MOSFET are the maost commercial advanced devices. Each
device has characteristics that complement each other in some
respects. Power Bipolar Transistors have lower conduction losses
in the on-state, larger blocking voltages, but low switching
speed. In contrast Power MOSFETs can switch faster, but conduction
losses in on-state are higher. Nowadays, the new structure has
been designed in order to overcome to the performance limitations
of Power Bipolar Transistor and Power MOSFET. Such the device
is know as the Insulated Gate Bipolar Transistor (IGBT). This
device has significant superior characteristics for low and
medium frequency applications compared to Power Bipolar Transistors
and Power MOSFETs. Furthermore, its power rating can be improved
by increasing both current and volttage. For this reason, this
device more preferable over Power Bipolar Transistors and Power
MOSFETs in many electronic systems and applications. Thedesign,
the fabrication process, the packing assembly and the experimental
results of discrete planar and vertical IGBT are studied and
reported in this thesis. The device is fabricated by using the
double diffusion technique N/P+ type silicon epitaxial initial
wafers. With the combination of MOS gate structure and bipolar
current conduction, the IGBT structure can give not only a very
high input impedance but also the high operating forward current
density. However, on the other side, such a structure has a
parasitic P-N-P-N thyristoe occurs between its collector and
emitter terminals. This parasitic structure causes the latch-up
effect in IGBT that makes the current to be no longer controlled
by the MOS gate. This research begins with a study on parameters
that can affect current conduction capability, on-resistance,
breakdown voltage and switching speed.
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