Do you mean the difference between them or some circuit configaration?
'Insulated Gate Bipolar Transistor' is basically a power transistor with an integrated mosfet driver so it can be controlled with a voltage at high speeds. It can be turned on and off.
A 'Silicon Controlled Rectifier' just has a gate, once turned on, it will stay on untill the current falls below a threshold. There are also some new devices GCT, Gate Controlled Thyristors that can be turned on and off.
Lets list all SCR’s
GTO – Gate Turn-off Thyristor
IGCT – Integrated Gate Controlled Thyristor
MCT – MOS Controlled Thyristor
EST – Emitter Switched Thyristor
GTO and IGCT it’s current controlled devices. For turn-off it you should extract carriers out of base.
EST – for turn-off switched off cathode current
MCT – fully gate controlled device. Turn-on voltage is positive, turn-off voltage is negative.
If you compare cross-section view IGBT and MCT you’ll see not so much differences.
In MCT added p+source region and no p-base contact with cathode terminal.
Here is 3D cross-section MCT
In IGBT all use in Half and Full drive in Power electronic and SCR all use Phase shift Power control and dimming .You can read text book in Power Electronics: Converters, Applications, and Design By Ned Mohan, Tore M. Undeland, William P. Robbins . Wiley Book