A microfluidic MEMS device for inkjet printing, comprising a plurality of ejector elements, each ejector element including: a first region accommodating a first fluid flow channel (50; 51) and an actuator chamber; an actuator, accommodated within the actuator chamber; a second region accommodating a fluid containment chamber fluidically coupled to the inlet channel (50; 51), the second region comprising: a membrane layer of a first material coupled to the first region, the membrane layer having a first surface closing the actuator chamber and carrying the actuator and a second surface, opposite to the first surface; a membrane definition layer of a second material, coupled to the membrane layer and having a membrane definition opening, the membrane definition opening having a width in a laying plane of the membrane definition layer, the membrane definition layer being surrounded by a first protective layer of a third material; a second protective layer of a fourth material covering the membrane layer on the second surface, and a chamber delimiting body, coupled to the membrane definition layer through the first protective layer and having a chamber delimiting opening; and a third region, mechanically coupled to the second region and accommodating a second fluid flow channel, fluidically coupled to the fluid containment chamber; wherein the fluid containment chamber is delimited by the membrane layer, by the membrane definition layer, by the chamber delimiting body and by the third region, the chamber delimiting opening has, in a direction parallel to the laying plane, a width greater than the width of the membrane definition opening, the membrane definition opening defines a flexible membrane in the membrane layer, and the first and the second material are a semiconductor material and the first and the second protective layer are of dielectric material. a first region accommodating a first fluid flow channel (50; 51) and an actuator chamber; an actuator, accommodated within the actuator chamber; a second region accommodating a fluid containment chamber fluidically coupled to the inlet channel (50; 51), the second region comprising: a membrane layer of a first material coupled to the first region, the membrane layer having a first surface closing the actuator chamber and carrying the actuator and a second surface, opposite to the first surface; a membrane definition layer of a second material, coupled to the membrane layer and having a membrane definition opening, the membrane definition opening having a width in a laying plane of the membrane definition layer, the membrane definition layer being surrounded by a first protective layer of a third material; a second protective layer of a fourth material covering the membrane layer on the second surface, and a chamber delimiting body, coupled to the membrane definition layer through the first protective layer and having a chamber delimiting opening; and a third region, mechanically coupled to the second region and accommodating a second fluid flow channel, fluidically coupled to the fluid containment chamber; wherein the fluid containment chamber is delimited by the membrane layer, by the membrane definition layer, by the chamber delimiting body and by the third region, the chamber delimiting opening has, in a direction parallel to the laying plane, a width greater than the width of the membrane definition opening, the membrane definition opening defines a flexible membrane in the membrane layer, and the first and the second material are a semiconductor material and the first and the second protective layer are of dielectric material. a membrane layer of a first material coupled to the first region, the membrane layer having a first surface closing the actuator chamber and carrying the actuator and a second surface, opposite to the first surface; a membrane definition layer of a second material, coupled to the membrane layer and having a membrane definition opening, the membrane definition opening having a width in a laying plane of the membrane definition layer, the membrane definition layer being surrounded by a first protective layer of a third material; a second protective layer of a fourth material covering the membrane layer on the second surface, and a chamber delimiting body, coupled to the membrane definition layer through the first protective layer and having a chamber delimiting opening; and a third region, mechanically coupled to the second region and accommodating a second fluid flow channel, fluidically coupled to the fluid containment chamber; wherein the fluid containment chamber is delimited by the membrane layer, by the membrane definition layer, by the chamber delimiting body and by the third region, the chamber delimiting opening has, in a direction parallel to the laying plane, a width greater than the width of the membrane definition opening, the membrane definition opening defines a flexible membrane in the membrane layer, and the first and the second material are a semiconductor material and the first and the second protective layer are of dielectric material.