Contact resistance

About: Contact resistance is a research topic. Over the lifetime, 15262 publications have been published within this topic receiving 232144 citations. The topic is also known as: electrical contact resistance & ECR.

Measurement of collector and emitter resistances in bipolar transistors

Abstract: New DC methods to measure the collector resistance R/sub C/ and emitter resistance R/sub E/ are presented. These methods are based on monitoring the substrate current of the parasitic vertical p-n-p transistor linked with the n-p-n intrinsic transistor. The p-n-p transistor is operated with either the bottom substrate-collector or the top base-collector p-n junction forward-biased. This allows for a separation of the various components of R/sub C/. R/sub E/ is obtained from the measured lateral portion of R/sub C/ and the collector-emitter saturation voltage. Examples of measurements on advanced self-aligned transistors with polysilicon contacts are shown. The results show a very strong dependence of R/sub C/ on the base-emitter and base-collector voltages of the n-p-n transistor. The bias dependence of R/sub C/ is due to the conductivity modulation of the epitaxial collector. From the measured emitter resistance R/sub E/ a value for the specific contact resistance for the polysilicon emitter contact of rho /sub c/ equivalent to 50 Omega - mu m/sup 2/ is obtained. >

Evaluation of ohmic contacts formed by B+ implantation and Ti‐Au metallization on diamond

Abstract: Low‐resistance ohmic contacts have been fabricated on a naturally occurring B‐doped diamond crystal and on polycrystalline diamond films by B ion implantation and subsequent Ti/Au bilayer metallization. A high B concentration was obtained at the surface by ion implantation, a post‐implant anneal, and a subsequent chemical removal of the graphite layer. A bilayer metallization of Ti followed by Au, annealed at 850 °C, yielded specific contact resistance (ρc) values of the order of 10−5 Ω cm2 for chemical vapor deposition grown polycrystalline films and the natural IIb crystal. The ρc values from transmission line model measurements on three different contact configurations, namely, standard rectangular pads, rectangular pads on diamond mesas, and three‐ring circular structures have been compared. These contacts were stable to a measurement temperature of ∼400 °C and no degradation due to temperature cycling was observed. Chemical analysis by x‐ray photoelectron spectroscopy (XPS) in conjunction with Ar+ sputter depth profiling of the annealed samples indicated that the Au overlayer was not effective in preventing oxidation of the underlying Ti. The XPS study also indicated the formation of TiC at the Ti/diamond interface.

Extremely Low Resistance Non-Alloyed Ohmic Contacts to n-GaAs Using Compositionally Graded InxGa1-xAs Layers

Abstract: Silicon doping in lattice-mismatched InxGa1-xAs (x=0, 02, 035, 065, 10) films grown on GaAs by MBE is studied The maximum carrier concentration for InxGa1-xAs is found to increase with the InAs mole fraction, x Based on this result, the x dependence of the specific contact resistance, ρc, for non-alloyed ohmic contacts to n-GaAs using compositionally graded InxGa1-xAs layers is also investigated It is found that ρc decreases with increasing x for x≤065, and an extremely low specific contact resistance of 5×10-8 Ωcm2 is obtained with 15×1019 cm-3 doped n+-In065Ga035As