Nonrectifying junction

In fabricating semiconductor devices, contact between the metal wires and the semiconductor material automatically creates p-n junctions called Schottky diodes. Such a semiconductor device would malfunction, since all of its terminals would contain diodes which act either as open circuits, or if forward biased, will possess unwanted voltage drops. But in practice, surface impurities within the part of the semiconductor which touches the metal terminals will greatly reduce the width of those depletion zones to such an extent that the metal/semiconductor junctions don't act as diodes. The forward voltage drop is very small, and during reverse bias the device breaks down and the potential barrier is nearly eliminated. These "nonrectifying junctions" essentially behave as always-on diodes regardless of applied voltage polarity. In effect this forms an Ohmic contact.

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