Characterization of Films with Thickness Less than 10 nm by Sensitivity-Enhanced Atomic Force Acoustic Microscopy

Table 1 Elastic moduli of reference samples

Reference sample	Young's modulus E_s(GPa)	Poisson's ratio (ν_s)	Effective Young's modulus $E_{s}^{*} = E_{s} / (1 - ν_{s}^{2})$ [GPa]
Diamond (100)	1050	0.1	1061
Sapphire (0001)	451.2	0.172	465.1
Silicon (111)	187.9	0.180	194.2
Silicon (100)	130.0	0.278	140.9