Identifying nano-Schottky diode currents in silicon diodes with 2D interfacial layers

In silicon technology, Schottky diodes mainly exhibit high current levels, and attempts are regularly made to reduce these by introducing 2D layers between the metal contact and the silicon. Defects in such interfacial layers, from weakly bonded structures to actual pinholes, can lead to high, localized metal-semiconductor Schottky currents. Using the example of diodes with an interfacial layer of pure boron (PureB) between an aluminum metallization layer and the Si, a signature for such ‘‘nano-Schottky’s’’ is determined by evaluating the results of several different test-structure arrays and measurement techniques. An adapted bipolar-type measurement is introduced as an additional method to determine whether any high current characteristics originate from a low Schottky barrier height over the entire diode surface or from a localized nano-Schottky structure.