Contacts to Wide-Band-Gap Semiconductors

Effect of ultrathin gold on the Ohmic-to-Schottky transition in Al/ZnO contacts: A first-principles investigation

“…However, the understanding and control of ZnO/metal contacts still represents a challenge, as shown by the wide range of barrier height values measured for the same metal on a given ZnO surface. This puzzling ZnO behavior exasperates a common phenomenon among wide-gap semiconductors, 3,4 and represents a manifest failure of simplified models that neglect the dependence of the Schottky barrier height (SBH) on the interface details, such as the Schottky-Mott rule, where the Schottky barrier is evaluated as the difference between the metal work function and the semiconductor electron affinity.…”

The Formation Mechanism of Ni-Based Ohmic Contacts to 4H-n-SiC

“…Commonly recognized difficulties in the fabrication of reliable and low-resistance ohmic contacts to SiC impede to take full advantage of excellent SiC properties with regard to high power high temperature electronic devices [1]. To solve this problem, deeper understanding of the mechanism of formation of ohmic contact is required; specifically more information on interfacial reactions at metal/SiC interface governing the transition from rectifying to ohmic contact is needed.…”

“…For n-type SiC, Ni-based contacts are the most commonly used ones and there are different explanations in the literature concerning their formation mechanisms [1]. The most controversial is the formation of nickel silicides [2] or graphitized carbon [3] at the contact/SiC interface.…”