Electrical characterization of Al/Si ohmic contacts to heavily boron doped polycrystalline diamond films

Abstract

Mesa etched transmission line model (TLM) test structures with different contact lengths have been fabricated on heavily boron doped polycrystalline diamond films. The behavior of the contact and contact end resistance measurements can be fully explained using the TLM. No influence of the grain size on the contact resistivity has been observed. High surface boron doping concentrations led to low contact resistivities, in agreement with numerical calculations. Annealing of Al/Si–diamond contacts at 450 °C in N2 leads to lower contact resistivities due the formation of SiC at the metal–diamond interface. The temperature dependence of the specific contact resistivity can be described well with a tunneling model before annealing. After annealing no useful fit is possible, indicative of the fact that the SiC interface layer acts as defect layer.

High—temperature Sensors Based on SiC and Diamond Technology

“…Doping concentrations higher than 10 21 cm ±3 have been reported for borondoped diamond. In qualitative agreement with the theory, the contact resistivity drops with increased doping concentration [63]. On the one hand, large barrier heights lead to high contact resistivities.…”

“…Therefore, barrier heights in the region of 1.8 eV for diamond can be expected. Reported barrier heights range from 1.1 to 2.2 eV [63]. The most conventional way to obtain low contact resistivities is heavy doping of the contact area either by ion implantation or in situ doping during growth.…”

Characterization of contact resistance between electrode and TaNx thin‐film resistor prepared by reactive sputtering

“…When the sheet resistance of the Au electrode and the interfacial layer is sufficiently low and can be neglected, the resistance R e of the electrode is expressed by [4] where w is the sample width and l is the electrode length.…”

“…In this research, we look at the contact resistance between the electrode and the TaN x thin film as this structure, develop TaN x thin film having different nitrogen concentrations by RF reactive sputtering, and evaluate its TCR. To evaluate the isolation from other elements by the contact resistance, we calculated the specific contact resistivity from the TLM [4].…”

Diamond as substrate for 3C‐SiC growth: A TEM study

“…However, since SiC is inert with respect to diamond, growing SiC-related device structures on diamond can join the advantage of maturity to other diamond-related characteristics. In particular, it can be an alternative to improve local technological problems as ohmic contacts as Al/Si [2,3], Au/Ta [4], or Mo [5]. Nevertheless, just a few authors have studied SiC growth on diamond [6,7] most probably due to the difficulties related to this heterosystem.…”