Understanding extracted Richardson constant in Schottky diodes using Ni/GaN as a case study

Abstract

Optimizing the metal/semiconductor Schottky interface is essential for enhancing device performance. Current transport across such interfaces is characterized by a Schottky barrier height, temperature, and the Richardson constant (A∗). A large spread in A∗ is observed for Schottky diodes, often with values far smaller than theoretically predicted. Temperature-dependent current–voltage measurements are performed for a nickel (Ni)/gallium nitride (GaN) Schottky diode. Using the Ni/GaN diode as a case study, electron transport across the device is investigated using an effective mass-based quantum transmitting boundary method to accurately account for the large quantum mechanical reflections at the Ni/GaN interface. The calculated A∗ is in good agreement with the measured value, highlighting the importance of accurately accounting for tunneling, and reflections at the metal/semiconductor interface in explaining the variation in A∗ values reported in literature.