Titanium disilicide contact resistivity and its impact on 1-µm CMOS circuit performance

Systematic TLM Measurements of NiSi and PtSi Specific Contact Resistance to n- and p-Type Si in a Broad Doping Range

“…Moreover, some values for NiSi can be found in the literature [4]- [7], but no solid database for NiSi-silicon contact resistance exists, particularly for a broad range of doping levels. Most of the research studying ρ c used cross-bridge Kelvin resistor (CBKR) structures, while in modern IC technology, one would tend to use transmission-line model (TLM) structures as they could be easier embedded in the standard self-aligned silicide CMOS process [8]. The advantage of the TLM structure over the CBKR one is that, in TLM structures, the silicide segments and the contact pads are made in one single-salicide process step.…”

“…On the other hand, PtSi has been studied thoroughly [3], [17]- [19], providing a good reference. Silicideto-silicon contact resistance was investigated using a set of optimized test structures with silicided segments of varying lengths, based on the Scott model for TLM structures [8], [20]. The validity of our results is based on the following: 1) systematic measurements and statistical data analysis (i.e., the represented data were averaged over 18 dies for each doping type and concentration), 2) experimental verification of the actual active doping concentrations and doping profiles by secondary ion-mass spectrometry (SIMS) and spreadingresistance-probe (SRP) techniques, 3) verification of the actual silicide lengths for different silicide segments by TEM analysis, and 4) optimizing the TLM structures in terms of the silicide lengths and the number of segments.…”

Specific contact resistance measurements of metal-semiconductor junctions

“…The theoretical expression of the contact resistance contribution to the series source and drain resistance is expressed as [5]:…”

“…The extraction of the contact resistance contribution to the series source and drain resistance cannot be done using transistor measurements; appropriate test structures are necessary for contact resistance evaluation. The transmission line structure [5] is a useful and simple method to accurately describe the behavior of the silicide contact resistance. Silicide to silicon contact resistance is investigated using a set of dedicated test structures with silicided segments of varying lengths based on the Scott model [6].…”

“…Thus the ability to accurately measure the contact resistance is essential to contact process development. For this purpose, a set of test structures was fabricated and specific contact resistance was derived using the Scott model of TLM [5] and a correction for the current distribution.…”