Phase State Analysis of Nickel Silicides in Complementary Metal–Oxide–Semiconductor Device Using Plasmon Energy Map

Abstract

Phase states of nickel silicides in a complementary metal-oxide-semiconductor (CMOS) device were investigated using energy-filtering transmission electron microscopy (EF-TEM). Differences in plasmon energy at each location of the device were identified in two dimensions using a plasmon energy map to analyze the phase states of nickel silicides. We determined that the near side of polycrystalline silicon (poly-Si) corresponds to the NiSi phase in the gate electrode and that the contact corresponds to the NiSi 2 phase, although determining the different phase states of nickel silicides using the contrast of a TEM image was difficult.

Characterization of Ultra-Thin Ni Silicide Film by Two-Step Low Temperature Microwave Anneal

“…The readily observed bulk-plasmon excitations of NiSi 2 (19.7 eV) and NiSi (20.3 eV) in Fig. 4a are also nicely consistent with the known values of the respective materials, 10 in agreement with the STEM-EELS characterizations in Fig. 3.…”

“…A 4.5 nm NiSi film with very few NiSi 2 nano-islands, sample C, could be achieved by using setup 1 chamber with lower microwave power, 540 W, for the first step MWA. The maximum temperature on the process wafer surface is 233 • C. Figures 2a ∼ 2e show the [1][2][3][4][5][6][7][8][9][10] Si substrate cross-sectional HRTEM images of thin silicide layers. Figure 2a shows a typical thin silicide layer with partial crystalline and unreacted Ni (on top) was formed by the first step MWA of sample B.…”

“…16 As the silicide thickness is pushed to below 10 nm after RTA or MWA process, in experience, it is easy to form nano structures with NiSi 2 phases in the silicide layer. [17][18][19] Figure 3 shows the [1][2][3][4][5][6][7][8][9][10] Si substrate high-resolution HAADF image of the 4.5 nm NiSi sample, with the brightest contrast signifying NiSi (green inset, Fig. 3) and the bright one in the right inset directing to NiSi 2 (red inset, Fig.…”

“…8 It is well recognized that identification of nickel silicide phases after annealing is of crucial importance to its performance, especially, while these phases are formed in nano-polycrystalline layer. In this study, we use electron energy-loss spectroscopy [9][10][11][12][13] and energy dispersive X-ray spectroscopy 13,14 in conjunction with scanning transmission electron microscopy 14 (STEM-EELS/EDS) in order to identify the nickel silicide phases concentrating primarily on the Z-contrast image with atomic spatial resolution, elemental analysis, bulk plasmon excitaions and the chemical bonding.…”