A microcavity structure including: a first substrate, a cover attached to the first substrate such that a space formed between the cover and the first substrate forms the microcavity, at least one hole passing through the cover, and at least one closing flap of the hole placed inside the microcavity and including at least two portions of materials with different thermal expansion coefficients placed one against the other, at least one first end of the two portions being mechanically linked to the cover, at least a second end of the two portions being free, and at least a part of the closing flap being placed opposite the hole, the two portions being capable of closing or not the hole under the effect of a temperature variation.