Backward diode
![Band diagram of a backward diode. Electron energy is on the vertical axis, position within the device is on the horizontal axis. The backward diode has the unusual property that the so-called reverse bias direction actually has more current flow than the so-called forward bias.](/Images/godic/202412/22/Backward_Diode_Band_Diagram.svg3312.png")
In semiconductor devices, a backward diode (also called back diode) is a variation on a Zener diode or tunnel diode having a better conduction for small reverse biases (for example –0.1 to –0.6 V) than for forward bias voltages.
The reverse current in such a diode is by tunneling, which is also known as the tunnel effect.