Temperature sensor and method for producing same
Provided are a temperature sensor that is hard to increase resistance in the electrode structure with respect to a Ti—Al—N thermistor material layer even under a high-temperature environment, and has a high reliability with a high heat resistance as well as a method for producing the same. The temperature sensor includes an insulation substrate; a thin film thermistor portion formed on the insulation substrate; and a pair of pattern electrodes formed on the insulation substrate with a pair of opposed electrode portions being arranged so as to be opposed to each other on the thin film thermistor portion, wherein the thin film thermistor portion is made of a Ti—Al—N thermistor material, and the pair of pattern electrodes has a Ti—N bonding layer formed on the thin film thermistor portion and an electrode layer made of a noble metal formed on the bonding layer.
1. A temperature sensor comprising:
an insulation substrate;
a thin film thermistor portion formed on the insulation substrate; and
a pair of pattern electrodes formed on the insulation substrate with a pair of opposed electrode portions being arranged so as to be opposed to each other on the thin film thermistor portion,
wherein the thin film thermistor portion is made of a Ti—Al—N thermistor material,
the pair of pattern electrodes has a Ti—N bonding layer formed directly on the thin film thermistor portion and an electrode layer made of a noble metal formed on the bonding layer, and
the Ti—N bonding layer has a bondability to the thin film thermistor portion and the electrode layer, respectively.
2. The temperature sensor according to claim 1 , wherein the insulation substrate is an insulation film.
3. The temperature sensor according to claim 1 , wherein the thin film thermistor portion consists of a metal nitride represented by the general formula: Ti x Al y N z (where 0.70≤y/(x+y)≤0.95, 0.4≤z≤0.5, and x+y+z=1), wherein the crystal structure thereof is a hexagonal wurtzite-type single phase.
4. A method for producing the temperature sensor according to claim 1 , the method comprising the steps of:
forming a film thermistor portion for patterning the thin film thermistor portion on the insulation substrate;
forming an electrode for patterning the pair of pattern electrodes on the insulation substrate with the pair of opposed electrode portions being arranged so as to be opposed to each other on the thin film thermistor portion,
wherein the step of forming a film thermistor portion includes a step of patterning the Ti—Al—N thin film thermistor portion on the insulation substrate,
the step of forming an electrode includes the steps of:
depositing the bonding layer on the thin film thermistor portion and the insulation substrate;
depositing the electrode layer on the bonding layer;
etching the deposited electrode layer so as to be patterned into a predetermined shape; and
etching the deposited bonding layer using Ti etchant, the Ti etchant selectively etches the Ti—N bonding layer among the Ti—Al—N thin film thermistor portion and the Ti—N bonding layer, so as to be patterned into a predetermined shape.