Characteristics of Al/Ge Schottky and ohmic contacts at low temperatures

Schottky barrier contact has been fabricated by thermal deposition of Al on (100) p-Ge (impurity concentratioñ1010/cm3 at 80K) that shows n-type conductivity above 180K due to thermally generated carriers. Both p and Ge exhibits ideal behavior with low reverse current near unity ideality factors obtained from the linear form temperature dependent current-voltage (I–V) characteristics. The diode various temperatures change its direction non-zero applied bias reflects a shift in position charge neutrality level (CNL) Fermi Ge. With rise temperature, height (SBH) steadily increases for can be understood basis observed variation CNL. Values SBH determined zero Richardson plot agrees well estimated Schottky-Mott rule strongly pinned interface. Activation energies are forward voltages found decrease n-Ge but reduces work function similar Al. Annealing Al/Ge induces regrowth p-type doped layer gradual reduction concentration towards crystal. (p+)/Ge (p) junction thus I–V characteristics extrinsic region (below 180K). In intrinsic (above 180K), rectification is curve both