Pressure-sensing element including a guard and a membrane including a trench, and pressure sensor including pressure-sensing element

A pressure-sensing element comprising:

• a membrane including a diaphragm;
• a substrate opposite to the membrane in a thickness direction;
• a guard between the membrane and the substrate and bonded to the membrane and the substrate, the guard having a closed shape;
• and
• a base in an enclosed space defined by the membrane, the substrate, and the guard, the base being bonded to the membrane and being spaced away from the substrate and the guard;
• wherein
• a portion of a surface of the base closer than another surface of the base to the membrane is opposed to the diaphragm with a pressure reference chamber located between the portion of the surface and the diaphragm to provide electrostatic capacitance between the base and the membrane;
• the base, except for the portion of the surface of the base closer than the other surface of the base to the membrane, is bonded to the membrane;
• one or more trenches with a depth direction coinciding with the thickness direction are provided at least in the guard;
• at least one of the one or more trenches is provided in the guard and the membrane and extends in the thickness direction entirely through the membrane and at least partially through the guard;
• the base includes a first electrode and a second electrode separate from the first electrode;
• the first electrode faces the pressure reference chamber;
• and
• the second electrode is bonded to the membrane with an insulator therebetween.

A pressure-sensing element comprising:

• a membrane including a diaphragm;
• a substrate opposite to the membrane in a thickness direction;
• a guard between the membrane and the substrate and bonded to the membrane and the substrate, the guard having a closed shape;
• and
• a base in an enclosed space defined by the membrane, the substrate, and the guard, the base being bonded to the membrane and being spaced away from the substrate and the guard;
• wherein
• a portion of a surface of the base closer than another surface of the base to the membrane is opposed to the diaphragm with a pressure reference chamber located between the portion of the surface and the diaphragm to provide electrostatic capacitance between the base and the membrane;
• the base, except for the portion of the surface of the base closer than the other surface of the base to the membrane, is bonded to the membrane;
• one or more trenches with a depth direction coinciding with the thickness direction are provided at least in the guard;
• at least one of the one or more trenches is provided in the guard and the membrane and extends in the thickness direction entirely through the membrane and at least partially through the guard;
• and
• the guard is electrically connected to the substrate.