The low-temperature behavior of the direct volt-ampere characteristics of Schottky-barrier diodes

Low-temperature tests (77 K) were performed on a number of GaAs Schottky-barrier diodes. It is shown that, in the absence of local thermal field emission, the growth of the ideality exponent (n) of the volt-ampere characteristics is connected only with the properties of the intermediate layer and surface electron states on the contact. It is shown that the effect of fundamental factors of current transfer, such as quantum-mechanical tunneling and the breakdown of the distribution function via the transmitted current, is negligible, since n is less than 1.1 at 77 K for a whole series of cases. It is also shown that the growth of n at 77 K depends on the type of metal and its thickness. It is assumed that the direct cause of the growth of n is an increase of surface-electron-state density at the bottom of the conduction zone, the appearance of these states being due to the irregular structure of the intermediate layer and the effect of mechanical stresses on the contact.