An application note from WIMA about snubber capacitors, Link here.
The trend of modern semiconductor technology towards increasingly powerful applications results in the fact that switched currents and voltage levels are continuously increased and that simultaneously the switching speed is also increasing markedly.
The developments in the area of power semiconductors include the component group IGBT (Insulated Gate Bipolar Transistor) or IGBT modules.
The switching capacity with shortest switching times which can be realized using IGBTs necessitates an extremely low-inductance circuit design. Even the low self-inductance of the power bus may induce dangerous voltage overshoots between collector and emitter which may result in the destruction of the valuable power semiconductors.
To protect the components, so-called snubber suppressor circuits are used. The most important component in this respect is a low-inductance pulse capacitor in order to attenuate or cut off peak voltages.