Patent ID: 8227021
Filing Date: 2012-07-24
Classification: B41J,H01L,Y10T

Abstract:
1. A method of manufacturing a piezoelectric thin film of perovskite crystals represented by a general formula Pb (1−x )La x (Zr y Ti 1−y )O 3 (where 0≦x<1, 0.05≦y≦1) and manufactured from a plurality of piezoelectric layers, wherein a surface of the piezoelectric thin film includes crystal grains having an equivalent circle diameter of 200 nm or more and crystal grains having an equivalent circle diameter of 40 nm or less, and a number of the crystal grains observed in the surface of the piezoelectric thin film and having the equivalent circle diameter of 40 nm or less is 5% or more with respect to a total number of the crystal grains observed in the surface of the piezoelectric thin film, the method comprising the steps in a following order of: (a) a first step of providing a first raw material solution containing titanium, zirconium, and lead on a substrate to thereby form a first coating layer; (b) a second step of firing the first coating layer at a temperature of 400° C. or more and 700° C. or less to thereby form a first piezoelectric layer having a layer thickness of 150 nm or more and 400 nm or less; (c) a third step of providing a second raw material solution containing titanium, zirconium, and lead on the first piezoelectric layer to thereby form a second coating layer; and (d) a fourth step of firing the second coating layer at a temperature of 400° C. or more and 700° C. or less to thereby form a second piezoelectric layer having a layer thickness of 150 nm or more and 400 nm or less, wherein a titanium concentration in the first step of providing the first raw material solution is higher than a titanium concentration in the third step of providing the second raw material solution, and wherein a difference between a maximum value and a minimum value of y in an arbitrary portion of the piezoelectric thin film is 0.05 or less.