Sensor and sensor system
According to one embodiment, a sensor includes a base, a base including a first region and a second region, a fixed electrode fixed to the first region, a first fixed portion fixed to the second region, a first support portion, and a movable portion. The first support portion is connected to the first fixed portion. The first support portion includes a first support layer and a first layer fixed to the first support layer. The first layer includes at least one metal selected from the group consisting of Pt, Pd and Ti, and oxygen. The movable portion is supported by the first support portion. A first gap is provided between the fixed electrode and the movable portion.
1 . A sensor, comprising:
a base including a first region and a second region;
a fixed electrode fixed to the first region;
a first fixed portion fixed to the second region;
a first support portion connected to the first fixed portion, the first support portion including a first support layer and a first layer fixed to the first support layer, the first layer including at least one metal selected from the group consisting of Pt, Pd and Ti, and oxygen; and
a movable portion supported by the first support portion, a first gap being provided between the fixed electrode and the movable portion,
wherein
the first layer includes a first face and a first portion,
the first portion is between the first support layer and the first face,
the first portion is a center of the first layer in a first direction from the first support layer to the first face, and
a ratio of an absolute value of a difference between a first portion concentration of oxygen in the first portion and a first face concentration of oxygen in the first face to the first portion concentration is not less than 0.1 and not more than 10.
2 . The sensor according to claim 1 , wherein
the first layer is configured to be reduced by a detection target gas around the first layer.
3 . The sensor according to claim 2 , wherein
the detection target gas includes hydrogen.
4 . The sensor according to claim 1 , wherein
a concentration of a detection target gas in a first state is higher than a concentration of the detection target gas in a second state, and
a first distance between the fixed electrode and the movable portion in the first state is longer than a second distance between the fixed electrode and the movable portion in the second state.
5 . The sensor according to claim 1 , wherein
a concentration of the detection target gas in a first state is higher than a concentration of the detection target gas in a second state, and
a first volume of the first layer in the first state is smaller than a second volume of the first layer in the second state.
6 . The sensor according to claim 1 , wherein
a concentration of the detection target gas in a first state is higher than a concentration of the detection target gas in a second state, and
a first electrical capacitance between the fixed electrode and the movable portion in the first state is smaller than a second electrical capacitance between the fixed electrode and the movable portion in the second state.
7 . The sensor according to claim 6 , further comprising:
a controller configured to detect the first electrical capacitance and the second electrical capacitance.
8 . The sensor according to claim 1 , wherein
the first layer includes an oxide of the metal.
9 . The sensor according to claim 1 , wherein
the first layer includes a bond between the metal and oxygen.
10 . The sensor according to claim 1 , wherein
a thickness of the first layer is not less than 1 nm and not more than 1 μm.
11 . The sensor according to claim 10 , wherein
a thickness of the first support layer is not less than 10 nm and not more than 10 μm.
12 . The sensor according to claim 1 , wherein
the first support portion further includes a first conductive member, and
a temperature of the first support portion can be increased by a current flowing through the first conductive member.
13 . The sensor according to claim 1 , wherein
the first support layer includes silicon oxide.
14 . The sensor according to claim 1 , wherein
the first support layer is provided between the base and the first layer, and
a second gap is provided between the base and the first support layer.
15 . The sensor according to claim 14 , further comprising:
a first connecting portion,
a part of the first connecting portion being connected to the first support portion,
another part of the first connecting portion being connected to the movable portion, and
a third gap being provided between the base and the first connecting portion.
16 . The sensor according to claim 15 , wherein
the first connecting portion has a meandering structure.
17 . The sensor according to claim 1 , further comprising:
a second fixed portion; and
a second support portion,
the base further including a third region,
the first region being between the second region and the third region,
the second fixed portion being fixed to the third region,
the second support portion being connected to the second fixed portion,
the second support portion including a second support layer and a second layer fixed to the second support layer, the second layer including at least one metal selected from the group consisting of Pt, Pd and Ti, and oxygen, and
the movable portion being provided between the first support portion and the second support portion and being further supported by the second support portion.
18 . The sensor according to claim 17 , further comprising:
a second connecting portion,
a part of the second connecting portion being connected to the second support portion,
another part of the second connecting portion being connected to the movable portion, and
a gap being provided between the base and the second connecting portion.
19 . The sensor according to claim 18 , wherein
the second connecting portion has a meandering structure.