SILICON DEVICE

PROBLEM TO BE SOLVED: To provide a silicon device having a structure which inhibits or prevents metal atoms in a ferroelectric layer from diffusing in a silicon layer and achieves the downsizing and the improvement of characteristics.SOLUTION: An ink jet printer head 1 serving as a silicon device includes: a silicon substrate 2; a silicon oxide layer 5B formed on the silicon substrate 2; a diffusion prevention film 70 formed on the silicon oxide layer 5B; and a piezoelectric element 6 provided on the diffusion prevention film 70. A compression chamber 62 serving as an ink accumulation part is formed on the silicon substrate 2, and a thin silicon layer 5A and the silicon oxide layer 5B, located on a top plate part of the compression chamber 62, form a vibration film 5. The piezoelectric element 6 includes: a lower electrode 7 contacting with the diffusion prevention film 70; a piezoelectric layer 8 provided on the lower electrode 7; and an upper electrode 9 provided on the piezoelectric layer 8. The diffusion prevention film 70 prevents the diffusion of metal atoms in the piezoelectric layer 8.