Characterization of Doped Diamondlike Carbon Films and Multilayers

Abstract

We have grown doped diamondlike carbon (DLC) thin films on Ni and Si substrates by mass separated low energy ion beam deposition. The current-voltage characteristics of these films and also a P-doped DLC / B-doped DLC diode-like device were measured. Doped DLC films show a higher electrical conductivity, which we interpret by hopping conductivity due to an increased density of localized states rather than a shift of the Fermi level. We also present first results on doping modulated DLC multilayers deposited on Si substrates. The dopant concentration profiles were analyzed by Rutherford Backscattering for63Cu dopant atoms and by neutron depth profiling for a10B doped multilayer.

Thermal stability of amorphous hard carbon films produced by cathodic arc deposition

“…It has been found by a number of authors using different deposition techniques that a carbon ion energy of about 100 eV is the optimum condition to produce films with the highest sp3 fraction. In some cases, substrate bias is applied to reach this energy, e.g., for laser ablation [1] and cathodic arc deposition [2][3][4][5], in some cases it results from ion beams of a given energy [6,7], or by a self biasing of the plasma in a plasma beam source [8]. Among the various deposition methods cathodic arc deposition produces some of the most "diamond-like" amorphous hard carbon films.…”

ta‐C/Si heterojunction diodes with apparently giant ideality factors

“…All of these electrical measurements were performed in the dark using a Keithley 237 Source-Measurement-Unit. The I-V characteristics of these films are already presented in the publications [12,20] and were interpreted in terms of Frenkel-Poole electric transport. However, a detailed analysis of the I-V characteristics was not given.…”

“…% increases the conductivity of these films indicating an increased density of localized states, but still with FrenkelPoole emission behavior. In addition, the forward bias I-V characteristics of ta-C/n-Si heterojunctions could be described by Frenkel-Poole conduction limited at higher bias voltages by an Ohmic contact resistance [12,20].…”

“…In this contribution, we report on the diode characteristics of Metal -Amorphous Semiconductor -Semiconductor diodes (MASS-diodes) based on tetrahedral amorphous carbon (ta-C). Therefore, we re-analyze I-V characteristics of ta-C and ta-C/Si heterojunction MASS-diodes described in our former publications of our group [12,20]. The ta-C thin films were deposited by mass selected ion beam deposition (MSIBD) onto crystalline 100 Si substrates.…”