Method for manufacturing a piezoelectric resonator

A method for manufacturing a piezoelectric resonator, an oscillating structure of the resonator being formed from a highly-doped silicon functional layer, the silicon functional layer being situated above a substrate with respect to a vertical direction and including a lateral main extension plane including a first lateral area, a second lateral area, and a third lateral area, a cavity being situated in the first lateral area below the silicon functional layer, the method comprising the following steps:

• depositing a piezoelectric layer on the silicon functional layer;
• depositing a silicon sacrificial layer on the piezoelectric layer;
• forming at least one recess in the second lateral area in such a way that a surface of the silicon functional layer is exposed inside the recess, the recess extending in the vertical direction via a silicon oxide sacrificial layer and the piezoelectric layer;
• forming a silicide layer on a surface of the silicon functional layer exposed inside the recess;
• forming a diffusion barrier layer on the silicide layer;
• removing the silicon oxide sacrificial layer;
• depositing and structuring a first and second metallization layer on the piezoelectric layer and the diffusion barrier layer, a supply line, which electrically conductively connects the first and third lateral area, being formed by the structuring of the first and second metallization layer and a first connection element being formed by the structuring in the second lateral area and a second connection element being formed in the third lateral area;
• and
• structuring the silicon functional layer and the piezoelectric layer in such a way that the oscillating structure is formed in the first lateral area, the silicon functional layer of the oscillating structure being electrically conductively connected to the first connection element via the silicon functional layer of the second lateral area and forming a lower electrode of the resonator, which electrically contacts via the first connection element, the first metallization layer of the oscillating structure being configured to be electrically contacted via the second connection element and forming an upper electrode of the resonator.