When a semiconductor device is brought in a strong electric field, the energy of the electrons/protons increases suddenly and because of this get trapped in areas of the semiconductor where they shouldn't be! and causes the device to degrade or become unstable. This happens mostly in MOS device. This effect is called "Hot Carrier Effect" [HCE] or "Hot Carrier Injection"
What is beta of a transistor ?
β (beta) of a transistor is the gain or amplification factor of a transistor. It is the factor by which current is amplified in the circuit. You must be familiar with amplifier devices, suppose you supply an input of 5A current and the amplifier is able to generate an output of 50A current, then the β of the transistor is 10.
How to differentiate between HCE and β ?
HCE defines the degree of degradation in a transistor and β defines the amplification factor of a transistor.