Low Schottky barrier height for ErSi2−x/n-Si contacts formed with a Ti cap

Abstract

Articles you may be interested inSchottky barrier heights of metal contacts to n -type gallium nitride with low-temperature-grown cap layerIn this paper, the formation of Er disilicide ͑ErSi 2−x ͒ with a Ti cap on low doping n-type Si͑100͒ is investigated. After deposition in ultrahigh vacuum, the solid-state reaction between Er and Si is performed ex situ by rapid thermal annealing between 450 and 600°C in a forming gas ambience with a 10 nm thick Ti capping layer to protect Er from oxidation. X-ray diffraction analyses have confirmed the formation of ErSi 2−x for all annealing temperatures. The formed films are found to be free of pinholes or pits and present a sharp and smooth interface with the Si bulk substrate. The extracted Schottky barrier height ͑SBH͒ corresponds to the state-of-the-art value of 0.28 eV if the annealing temperature is lower than or equal to 500°C. This result demonstrates the possibility to form low SBH ErSi 2−x / n-Si contacts with a protective Ti cap. However, when the annealing temperature is set to a higher value, the SBH concomitantly rises. Based on our experiments, this SBH increase can be mainly related to an enhanced diffusion of oxygen through the stack during the annealing, which degrades the quality of the ErSi 2−x film.

Infrared luminescence of erbium-silicon-oxide crystalline compound on silicon

“…5(a) and (b), respectively. Both samples had been annealed at 1200 °C for 1 h. Several peaks were identified as belonging to Errelated compounds as follows: ErSi 2-x at 2 = 27.1 °, ErO x at 2 = 29 °, Er-Si-O at 2 = 30.6 °, and Er 2 O 3 at 2 = 36 ° [25,26]. Therefore, several phases, including Er-Si-O, erbium silicide, and erbium oxide, formed at the interface between the evaporated layer and Si surface.…”

Contact resistivities of metal-insulator-semiconductor contacts and metal-semiconductor contacts

“…41 With rare earth silicides as contact metal, low / b $ 0.3 eV have been demonstrated for MS contacts. 49,50 For MIS contacts, as shown in Fig. 3, their q c correlates strongly with / b , t, m à ti , and DE C .…”

“…4, we see that the q c -N d curves of A, B, and C are almost in parallel, which means that the insulator in the MIS contacts augments q c by a similar degree for any N d . The advantage of the MIS contacts is most pronounced at relatively low doping levels, but it diminishes gradually with increasing N d -at ultrahigh doping levels, even the "ideal" MIS, A, cannot outperform its MS counterpart, D. Moreover, the existence of such an "ideal" MIS as A is suspicious: for instance, insulators with m à ti as low as 0.2 m 0 are uncommon; 46,50 insulators that have low DE C with semiconductors are rare; 44,46,50 moreover, there is usually a minimal insulator thickness of >1 nm required for an MIS to lower / b to 0.1 eV. 5,7,9,13 In conclusion, the MIS contacts are more appealing to the applications that use relatively low doped semiconductors, such as compound semiconductor devices and Si solar cells, while the MS contacts will still be the major force to push q c down below 1  10 À8 XÁcm 2 to meet the Complementary Metal-Oxide-Semiconductor (CMOS) requirement for the 10 nm technology node and beyond.…”

Monte Carlo Study of Dopant-Segregated Schottky Barrier SoI MOSFETs: Enhancement of the RF Performance

“…This thin, highly doped layer induces a strong band bending close to the contact enhancing the tunneling probability (and consequently also the drive current), as exemplified in [6]- [13]. Several authors have disclosed the advantages of DS layers, focusing on the reduced effective barrier height, the I -V curves, the parasitic contact resistance, the ON-OFF current ratio or the variation of the threshold voltage [6], [8], [12], [14]- [23] proving that the use of DS layers provides higher performance SB-MOSFETs for several analog and digital applications. However, few studies address the effects of the presence of a DS layer on the transconductance or cutoff frequency of SB-MOSFETs [17], [19], [24], [25].…”