High-barrier Al/p-Si Schottky diodes
Sequential implantation of argon ions and low-energy hydrogen ions has been found to yield Schottky barriers of exceptionally high values on p-type silicon. The interaction of these ions in Si is quite complex, involving donor defect generation, defect passivation, and acceptor dopant neutralization. The apparent synergism of these specific implants has resulted in Al/p-Si Schottky diodes with an effective barrier height as high as 0.83 eV, among the highest value reported for any metal/p-Si contact.
Schottky barrier height engineering of Al contacts on Si by embedded Au nanoparticles
Display Omitted By controlling the number of Au NPs on Si, the Al/Au NPs/Si SBH has been modified.Au NPs induced SBH lowering is more effective in Al/n-Si (0.11eV) compared with Al/p-Si (0.05eV).The size of NPs is the primary influential factor in local electric field enhancement.Other factors are Al/Au work function difference and Al/Si-Au/Si SBH difference.ETTI model was determined to best describe the Al/Au NPs/Si SBH lowering. Embedding metal nanoparticles (NPs) into metal contacts at metal-Si (MS) interface is an alternative method for modification of Schottky barrier height (SBH) and compared with traditional methods that might result in an undesired alteration of the MS interface, offers a tremendous simplification and adaptation in processing steps. There is a direct link between the type, size and density of NPs and their interaction with contact/semiconductor and the improved electrical characteristics. A comprehensive analysis of the NPs effect at MS interface is required to make appropriate and efficient selection of contact/NPs combination as well as deposition of NPs and fabrication of nanostructured contact. In this work, multiple successive deposition of colloidal Au NPs by spin-coating is used as an alternative and simple method to deposit Au NPs on n- and p-Si substrates. Electrical parameters of Au NPs/Al nanostructured contacts including SBH and ideality factor are in turn extracted from current-voltage characteristics. Two models of inhomogeneity in SBH and enhanced tunneling at triple interface are then invoked for further analysis of the NPs effect on electrical properties of contacts. The best model proposed to describe this phenomenology is the enhanced tunneling at triple interface.
Plasma etching of sputtered Mo and MoSi2 thin films in NF3 gas mixtures
Plasma etching characteristics of sputtered molybdenum and MoSi2 thin films using various NF3 gas mixtures in a planar reactor are presented. Anisotropic (vertical‐to‐lateral etch ratio of ∼3) edge profiles were obtained. The etch rates of Mo, MoSi2, doped poly‐Si, and SiO2 were determined as a function of rf current, reactor pressure, and NF3 concentration. At 1 A and 100 mTorr in 100% NF3, etch rates of 2490, 3440, 14000, and 670 A/min were measured for Mo, MoSi2, doped poly‐Si, and SiO2, respectively. Also, the etch rate ratios of Mo, MoSi2, doped poly‐ Si over SiO2 were 1.5–4, 4–8, and 12–24, respectively. Diluting the NF3 plasmas with argon or helium decreased the etch rates for all the materials studied here. At 200 mTorr and 1 A, the Mo etch rate dropped from 1800 A/min in 100% NF3 to 540 A/min in 20% NF3/80% Ar, while the corresponding silicide etch rate decreased from 7850 to 1130 A/min. Auger spectroscopy measurements inferred that the desorption of molybdenum products, but not the silicon ones,...