Schottky barrier height tuning of silicides on p-type Si (100) by aluminum implantation and pulsed excimer laser anneal

Abstract

We investigate the tuning of Schottky barrier height (SBH) of nickel silicide formed by pulsed excimer laser anneal of nickel on silicon implanted with aluminum (Al). A wide range of laser fluence was investigated, and it has been found that laser fluence influences the distribution of Al within the silicide and at the silicide/silicon interface. This in turn affects the effective whole SBH (ΦBp) at the silicide/silicon junction. High Al concentration at the silicide/silicon interface and high temperature for nano-second duration to achieve Al activation while keeping the Al concentration within the silicide low is vital for achieving low ΦBp. We demonstrate the achievement of one of the lowest reported ΦBp of ∼0.11 eV. This introduces a new option for forming nickel silicide contacts with reduced contact resistance at low thermal budget for possible adoption in future metal-oxide-semiconductor transistor technologies.

The physics and chemistry of the Schottky barrier height

“…144,307,[378][379][380][381][382][383][384][385][386][387][388][389][390] However, the net effect of interfacial chalcogen varied, as both significant increases 307 and decreases 386 in the n-type SBH were observed. To introduce impurities such as metals, [391][392][393][394][395] dopants, 348,389,390,[396][397][398][399][400][401][402][403][404] semiconducting, 405,406 and insulating 407 elements to the MS interface, various other methods have also been used, including deposition, ion implantation, segregation, etc. As shown in Fig.…”

Improving metal/semiconductor conductivity using AlOx interlayers on n-type and p-type Si

“…6). Sinha et al 24 and Koh et al 31 have reported the tuning of SBH at NiSi/p-Si junction by the introduction of Al using ion implantation and its segregation after silicidation. They attributed this effect to the higher probability of holes tunnelling through a thin barrier.…”

Tuning of Schottky Barrier Height at NiSi/Si Contact by Combining Dual Implantation of Boron and Aluminum and Microwave Annealing

“…However, an obvious discrepancy was observed between N2 and N4 as shown in Figure 4 : a higher implantation energy of Al resulted in a higher Al concentration at the interface accompanied by a higher density of Al remaining in the NiSi film. Previous studies have indicated that Al has a dual-barrier tuning effect [ 18 , 38 ], including reducing φ bn when incorporated with nickel silicide [ 39 , 40 , 41 ] and reducing φ bp at NiSi/Si interfaces. It has been reported that the incorporation of Al in NiSi could reduce the metal work function of NiSi by up to 400 meV [ 39 ].…”

“…Therefore, taking the two stages into consideration, the trade-off between the implantation energy and MWA power was attributed to the contradiction between the reduction and elevation of φ bn of Al as well as that between the concentration of Al remaining in NiSi and that accumulated at the NiSi/Si interface. To overcome this contradiction and achieve higher φ bn with lower MWA power, a thinner film of silicide [ 16 ] or a lower dose of Al [ 18 ] could be employed to sharpen the segregation peak at the NiSi/Si interface in future applications.…”

“…Because of the solubility limit of B in silicon, there is little room to further exploit the capacity for SBH regulation using mono-implantation of B [ 11 ]. It has been reported that aluminum (Al) DS can reduce the φ bp value to 0.11 eV in NiSi/p-Si contacts [ 16 , 17 , 18 ] and that indium DS can reduce this value to 0.16 eV [ 19 ]. According to Shannon, a p-type dopant could also be used to tune φ bp in an n-type substrate and vice versa [ 20 ].…”