Electrical characterization of inhomogeneous Ti/4H–SiC Schottky contacts

Silicon Carbide Schottky Barrier Diode

“…Barrier height inhomogeneous has also been investigated as a possible reason of a much larger reverse leakage current than predicted by the thermionic emission current in the SiC SBD [120][121][122][123]. It was suggested in [120] that there are localized regions at the SiC/metal interface where Schottky barrier height is lowered due to the presence of epitaxial layer defects at the interface.…”

Radiation effects on ohmic and Schottky contacts based on 4H and 6H-SiC

“…Both metals were evaporated through shadow masks sequentially as produced previously in our study [19], in a Univex-300 Pump system with a pressure of 4 Â 10 À5 Torr. In order to obtain good contact properties, ohmic contacts were annealed in a homemade furnace under dry N 2 gas flow at 950°C for 10 min [20].…”

A study of temperature-related non-linearity at the metal-silicon interface

“…Tung states 9 that at low temperature, Ohmic effects within the few conducting patches cause the dual current paths to become deconvoluted. This might explain the frequently cited and debated double bumps that can be seen variously in Si Schottky diodes 9,11 , SiC diodes [16][17][18][19][20] , GaAs diodes 23,24 , and also in heterojunctions 12,25 . The worsening of these effects in devices without guard rings or other edge protection, could futher be explained by low SBH patches at the device extremities which are not pinched off as well as those in the centre of the device, these being surrounded on all sides by the higher background patches [9][10][11] .…”

“…Other applications include carbon nanotube Schottky barrier transistors 6 , and Schottky solar cells, with materials including lead selenide nanocrystals 7 and graphene 8 . Despite over a hundred years of research and development into Schottky barriers, across all popular semiconductors and for the various applications, we still find ourselves with unanswered questions as to the nature of current flow across the barrier, especially in light of inhomogeneity at the metal-semiconductor interface 9,[11][12][13][14][15][16][17][18][19][20][21][22][23][24] , which can result in multiple conduction paths through the non-uniform interface. Sources of interfacial inhomogeneity include processing remnants (dirt, contamination), surface roughness, native oxide, an uneven doping profile, crystal defects and grain boundaries 9,11,12 and it is generally now accepted that the surface is better represented as a random array of different patches, each of varying barrier height and area, as represented in the inset of Figure 1a.…”

“…Interfacial inhomogeneity has been cited 9-24 as the cause for many experimental results that deviate from this response. These so called non-linearities include high ideality factors 9,11,13 , the discrepancy between Schottky barrier heights (SBH) extracted via CV and IV techniques [9][10][11][12][13][14][15] , the "T 0 anomaly" 9,11,13 , double bumps within the semi-log turn-on characteristics 9,11,13,[16][17][18][19][20] , edge effects 9,11 and non-linearity within Richardson plots 22 . It was the papers written by Tung [9][10][11] however, that first introduced a model that adapted Equation 1 to fully explain the non-linearities in light of interfacial inhomogeneity and SBH fluctuation.…”