A microelectromechanical resonator device comprising - a support structure, - a doped semiconductor resonator, - at least one anchor suspending the resonator to the support structure, - an actuator for exciting resonance into the resonator, characterized in that the resonator comprises a monolithic structure formed by a base portion and at least four protrusions (22A, 22B, 22C, 22D) extending outward from the base portion, wherein the monolithic structure is doped with an n-type doping agent to an average doping concentration of at least 2.3 ∗ 10 19 cm -3, and the resonator is excitable by said actuator into a compound resonance mode comprising a bulk acoustic wave resonance mode in the base portion and a flexural resonance mode in at least one of the at least four protrusions (22A, 22B, 22C, 22D) and said compound resonance mode having temperature coefficient of frequency, TCF, characteristics, which are contributed by both the base portion and the at least four protrusions (22A, 22B, 22C, 22D), and the TCFs of the base portion and the at least four protrusions (22A, 22B, 22C, 22D) have opposite signs within at least one temperature region, wherein an operational temperature range of the resonator is from -40 °C to 85°C; and - the base portion of the resonator is a rectangular plate having an aspect ratio greater than 1, in particular about 1:1.5, 1:2.7, 1:4.3, 1:5.5, 1:7.0, 1:8.7 with 5% accuracy, and with one main axis directed along the crystal direction of the semiconductor material within the limits of +/- 5°, wherein the aspect ratio is the ratio between the width and the length of the rectangular plate, and the at least four protrusions (22A, 22B, 22C, 22D), wherein each protrusion is a flexural beam, are symmetrically arranged at the perimeter of the base portion, wherein at least a main part of the four or more flexural beams is directed essentially along the or the crystal direction, or in the lateral plane into the direction, of the semiconductor material within the limits of +/- 5°, or in a direction of 20 - 70 degrees with respect to the main axis of the base portion and from the perimeter of the base portion, or - the resonator is a Lamé-mode resonator having a square-shaped base plate (33, 35), wherein the four or more flexural beams extend from the square-shaped base plate (33, 35) at an angle of 45 degrees within the limits of +/- 5 degrees, wherein the protrusions are symmetrically arranged at the perimeter of the base plate. - a support structure, - a doped semiconductor resonator, - at least one anchor suspending the resonator to the support structure, - an actuator for exciting resonance into the resonator, characterized in that the resonator comprises a monolithic structure formed by a base portion and at least four protrusions (22A, 22B, 22C, 22D) extending outward from the base portion, wherein the monolithic structure is doped with an n-type doping agent to an average doping concentration of at least 2.3 ∗ 10 19 cm -3, and the resonator is excitable by said actuator into a compound resonance mode comprising a bulk acoustic wave resonance mode in the base portion and a flexural resonance mode in at least one of the at least four protrusions (22A, 22B, 22C, 22D) and said compound resonance mode having temperature coefficient of frequency, TCF, characteristics, which are contributed by both the base portion and the at least four protrusions (22A, 22B, 22C, 22D), and the TCFs of the base portion and the at least four protrusions (22A, 22B, 22C, 22D) have opposite signs within at least one temperature region, wherein an operational temperature range of the resonator is from -40 °C to 85°C; and - the base portion of the resonator is a rectangular plate having an aspect ratio greater than 1, in particular about 1:1.5, 1:2.7, 1:4.3, 1:5.5, 1:7.0, 1:8.7 with 5% accuracy, and with one main axis directed along the crystal direction of the semiconductor material within the limits of +/- 5°, wherein the aspect ratio is the ratio between the width and the length of the rectangular plate, and the at least four protrusions (22A, 22B, 22C, 22D), wherein each protrusion is a flexural beam, are symmetrically arranged at the perimeter of the base portion, wherein at least a main part of the four or more flexural beams is directed essentially along the or the crystal direction, or in the lateral plane into the direction, of the semiconductor material within the limits of +/- 5°, or in a direction of 20 - 70 degrees with respect to the main axis of the base portion and from the perimeter of the base portion, or - the resonator is a Lamé-mode resonator having a square-shaped base plate (33, 35), wherein the four or more flexural beams extend from the square-shaped base plate (33, 35) at an angle of 45 degrees within the limits of +/- 5 degrees, wherein the protrusions are symmetrically arranged at the perimeter of the base plate.