Abstract: A bulk acoustic wave (BAW) resonator includes a piezoelectric layer oriented so that an N-polar surface forms a frontside surface that faces away from the substrate while a metal-polar surface forms the backside surface and faces toward the substrate. A process for the manufacture of a bulk acoustic wave (BAW) resonator includes orienting a piezoelectric layer on a substrate so that an N-polar surface forms a frontside surface that faces away from the substrate while a metal-polar surface forms the backside surface and faces toward the substrate; etching a via though the backside of the substrate to the metal-polar surface of the piezoelectric layer; and removing etch residue from a sidewall of the resonator cavity.

Abstract: A strain compensated heterostructure comprising a substrate comprising silicon carbide material; a first epitaxial layer comprising single-crystal aluminum nitride material formed on a top surface of the substrate; a second epitaxial layer formed on the first epitaxial layer opposite the top surface of the substrate, the second epitaxial layer comprising single-crystal scandium aluminum nitride material; and a third epitaxial layer formed on the second epitaxial layer opposite the first epitaxial layer, the third layer comprising single-crystal aluminum nitride material.

Abstract: A bulk acoustic wave (BAW) resonator includes a piezoelectric layer oriented so that an N-polar surface forms a frontside surface that faces away from the substrate while a metal-polar surface forms the backside surface and faces toward the substrate. A process for the manufacture of a bulk acoustic wave (BAW) resonator includes orienting a piezoelectric layer on a substrate so that an N-polar surface forms a frontside surface that faces away from the substrate while a metal-polar surface forms the backside surface and faces toward the substrate; etching a via though the backside of the substrate to the metal-polar surface of the piezoelectric layer; and removing etch residue from a sidewall of the resonator cavity.

Abstract: A strain compensated heterostructure comprising a substrate comprising silicon carbide material; a first epitaxial layer comprising single-crystal aluminum nitride material formed on a top surface of the substrate; a second epitaxial layer formed on the first epitaxial layer opposite the top surface of the substrate, the second epitaxial layer comprising single-crystal scandium aluminum nitride material; and a third epitaxial layer formed on the second epitaxial layer opposite the first epitaxial layer, the third layer comprising single-crystal aluminum nitride material.

Abstract: A primary cell having an anode comprising lithium and a cathode comprising iron disulfide (FeS2) and carbon particles. The electrolyte comprises a lithium salt dissolved in a nonaqueous solvent mixture which contains an alkyl ester, preferably an alkyl acetate. The electrolyte solvent may also include an organic cyclic carbonate. A cathode slurry is prepared comprising iron disulfide powder, carbon, binder, and a liquid solvent. The mixture is coated onto a conductive substrate and solvent evaporated leaving a dry cathode coating on the substrate. The anode and cathode can be spirally wound with separator therebetween and inserted into the cell casing with electrolyte then added.