An ohmic contact or Schottky barrier is formed when a metal and a p-type semiconductor are brought into contact. In the ideal case, the magnitude of the band bending ${\displaystyle V_{bi}}$ and contact resistance depend on the doping of the semiconductor, its dielectric constant and the Schottky barrier ${\displaystyle \phi _{B}=E_{g}-(\phi _{M}-\chi _{S})}$ where ${\displaystyle \phi _{M}}$ is the work function of the metal and ${\displaystyle E_{g}}$ is the bandgap and ${\displaystyle \chi _{S}}$ the electron affinity of the p-type semiconductor.