A bulk-acoustic wave resonator includes a substrate, a first electrode disposed on the substrate, a piezoelectric layer, of which at least a portion is disposed on the first electrode, a second electrode disposed on the piezoelectric layer, and a passivation layer disposed to cover the first electrode and the second electrode. Either one or both of the first electrode and the second electrode includes an aluminum alloy layer. Either one or both of the piezoelectric layer and the passivation layer has aluminum nitride, or aluminum nitride added with a doping material, having a ratio of an out-of-plane lattice constant “c” to an in-plane lattice constant “a” (c/a) of less than 1.58.

A method of manufacture and resulting structure for a single crystal electronic device with an enhanced strain interface region. The method of manufacture can include forming a nucleation layer overlying a substrate and forming a first and second single crystal layer overlying the nucleation layer. These first and second layers can be doped by introducing one or more impurity species to form the strained single crystal layers. The first and second strained layers can be aligned along the same crystallographic direction to form a strained single crystal bi-layer having an enhanced strain interface region. Using this enhanced single crystal bi-layer to form active or passive devices results in improved physical characteristics, such as enhanced photon velocity or improved density charges.

A method of manufacture and resulting structure for a single crystal electronic device with an enhanced strain interface region. The method of manufacture can include forming a nucleation layer overlying a substrate and forming a first and second single crystal layer overlying the nucleation layer. These first and second layers can be doped by introducing one or more impurity species to form the strained single crystal layers. The first and second strained layers can be aligned along the same crystallographic direction to form a strained single crystal bi-layer having an enhanced strain interface region. Using this enhanced single crystal bi-layer to form active or passive devices results in improved physical characteristics, such as enhanced photon velocity or improved density charges.

A nitride laminate, in which contamination in the nitride layer is suppressed and crystallinity is improved, is provided. A nitride laminate includes a polymer substrate, and a nitride layer provided on at least one of the surfaces of the polymer substrate. The nitride layer has a wurtzite crystal structure. The atomic proportion of oxygen in the nitride layer is 2.5 atm. % or less, and the atomic proportion of hydrogen in the nitride layer is 2.0 atm. % or less. The FWHM of the X-ray rocking curve of the nitride layer is 8 degree or less.

The present invention discloses an SOC PMUT suitable for high-density system integration, an array chip and a manufacturing method thereof. With the SOC PMUT suitable for high-density system integration, vertical stacking and monolithic integration of a SOC PMUT array with CMOS auxiliary circuits is realized by means of direct bonding of active wafers and a vertical multi-channel metal wiring structure; in addition, the extension to the package layer is implemented by means of TSVs, without any bonding mini-pad on the periphery of the array for communication with the CMOS. Thus, the bottleneck of metal interconnections in conventional ultrasonic transducers is overcome, the chip area occupied by metal interconnections in ultrasonic transducers is greatly reduced, the metal wiring length is reduced, thus the resulting adverse effects of an electrical parasitic effect on the performance of the ultrasonic transducer array are reduced.

A method for manufacturing an AlN-based laminate includes: forming on or above a substrate 210 a single-crystalline electrode layer 230 containing a metal element; and forming an AlN-based piezoelectric layer 240 on the electrode layer 230 by sputtering. Forming the piezoelectric layer 240 includes applying a pulse voltage to a target during the sputtering at a duty ratio of not more than 4% and at an average power density during pulse application of from 200 W/cm.sup.2 to 2500 W/cm.sup.2.

There are provided a piezoelectric film-attached substrate and piezoelectric element, which include, on a substrate in the following order, a lower electrode layer, a piezoelectric film containing a perovskite-type oxide containing lead as a main component of an A site, and a buffer layer, where the buffer layer contains a metal oxide represented by M.sub.dN.sub.1-dO.sub.e. Here, M consists of one or more metal elements substitutable for the A site of the perovskite-type oxide and has an electronegativity of less than 0.95. In a case of 0<d<1 and in a case where the electronegativity is denoted by X, 1.41X−1.05≤d≤A1.Math.exp(−X/t1)+y0, where A1=1.68×10.sup.12, t1=0.0306, and y0=0.59958.

There is provided a laminated substrate having a piezoelectric film, including: a substrate; and a piezoelectric film provided on the substrate interposing a base film, wherein the piezoelectric film has an alkali niobium oxide based perovskite structure represented by a composition formula of (K.sub.1-xNa.sub.x)NbO.sub.3 (0<x<1) and preferentially oriented in (001) plane direction, and a sound speed of the piezoelectric film is 5100 m/s or more.

A piezoelectric film on a substrate is provided comprising an aluminum nitride (AlN) layer, and a Al.sub.1-x(J).sub.xN compound layer comprising a graded section with a lower (J) composition, x, adjacent to the AlN layer and a higher (J) composition, x, located away from the AlN layer, the said (J) being a singular element or a binary compound. A method for forming such a piezoelectric film is also provided. A surface acoustic wave resonator comprising such a piezoelectric film, a surface acoustic wave filter comprising such a piezoelectric film, a bulk acoustic wave resonator comprising such a piezoelectric film, and a bulk acoustic wave filter comprising such a piezoelectric film are also provided.

A piezoelectric film on a substrate is provided comprising an aluminum nitride (AlN) layer, and a Al.sub.1-x(J).sub.xN compound layer comprising a graded section with a lower (J) composition, x, adjacent to the AlN layer and a higher (J) composition, x, located away from the AlN layer, the said (J) being a singular element or a binary compound. A method for forming such a piezoelectric film is also provided. A surface acoustic wave resonator comprising such a piezoelectric film, a surface acoustic wave filter comprising such a piezoelectric film, a bulk acoustic wave resonator comprising such a piezoelectric film, and a bulk acoustic wave filter comprising such a piezoelectric film are also provided.