Schottky barrier height engineering of Al contacts on Si by embedded Au nanoparticles

• 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 (0.11 eV) compared with Al/p-Si (0.05 eV).
• 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.

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