Compare, distinguish and explain what is the difference between schottky diode and pn diode.
What is the difference between pn diode and schottky diode ?
Difference between schottky diode and pn diode
1. In schottky diode, forward current is due to thermionic emission (majority carrier transport). In pn diode, forward current is due to diffusion currents (minority carrier transport).
2. In schottky, reverse current only due to majority carriers that overcome the barrier (less temperature dependent). In pn diode, reverse current due to minority carriers diffusing to the depletion layer and drifting to the other side (strong temperature dependence).
3. In schottky, cut-in voltage is small (about 0.3V). In pn, cut-in voltage is large (about 0.7V).
4. In schottkly diode there os high switching speed, because of majority carrier transport and so no recombination time needed. In pn diode, switching speed limited by the recombination time of the injected minority carriers.
5. Ideality factor about is about 1 in schottky because no recombination takes place in depletion layer. Ideality factor is about 1.2 to 2.0 in pn diode, which is due to recombination in depletion layer.