Table 2.

Properties of fused silica, 〈111〉 silicon, 7059 Corning glass, 211 Precision glass, and Z-cut quartz substrates: coefficient of thermal expansion (CTE), Young’s modulus (E_s), Poisson’s ratio (ν_s), E_s/(1 − ν_s²) calculated by using E_s and ν_s, reduced Young’s modulus E_r = E_s/(1 − ν_s²) and hardness (H) experimentally determined by nanoindentation, and thickness.

Substrate	CTE (10−6/°C)	Es (GPa)	νs	Es/(1 − νs²) (GPa)	Er (GPa)	H (GPa)	Thickness (μm)
Fused silica	0.55a	71.7a	0.17a	74	72 ± 1	10.0 ± 0.4	500
〈111〉 Si	2.6b	168.9b	0.262b	181	165 ± 6	10.1 ± 0.3	380
7059	4.6c	68.9c	0.20c	72	71 ± 0.2	7.4 ± 0.1	390
211	7.4d	74.5d	0.22 d	78	78 ± 2	7.4 ± 0.6	520
Z-cut Quartz	13.37e	76.5e	0.08e	77	109 ± 2	13.7 ± 0.5	500

^aSee ref.³⁹; ^bSee ref.^40,41; ^cSee ref.⁴²; ^dSee ref.⁴³; ^eSee ref.⁴⁴.