Other types of semiconductor diodes

The junction formed between a metal and a semiconductor can be either an ohmic junction or a rectifying junction. The leads or external contacts of a semiconductor device must under normal conditions form ohmic or nonrectifying junctions with the semiconductor. The junction between a metal and a semiconductor inside a metal-semiconductor diode must however, be a rectifying one. Such a diode is often called a Schottky diode. The external voltage-current characteristic curve of a Schottky diode is similar to that of a junction diode, but the physical mechanisms involved in the conduction process are more complicated.