Thermistor having doped and undoped layers of material
View Patent ↗According to some embodiments, a first layer of doped material may be provided to form a resistor. A second layer of undoped material may then be formed on the first layer. The first layer might comprise, for example, a layer of doped silicon carbide while the second layer comprises a layer of undoped silicon carbide. The resistance of the resistor may then be measured to determine a temperature.
1. A thermistor, comprising:
a first layer of doped material forming a resistor, wherein the first layer comprises wires of doped poly-silicon carbide; and
a second layer of undoped material formed on the first layer.
2. The thermistor of claim 1 , wherein the second layer is formed between the first layer of doped material and an external environment.
3. The thermistor of claim 1 , wherein the doped poly-silicon carbide of the first layer is doped via a low pressure chemical vapor deposition process.
4. The thermistor of claim 3 , wherein the doped poly-silicon carbide of the first layer is doped in-situ to form a microfabricated resistor.
5. The thermistor of claim 1 , wherein the second layer comprises a non-electrically conductive layer of at least one of: (i) undoped silicon carbide, (ii) silicon nitride, (iii) silicon dioxide or (iv) boron nitride.
6. The thermistor of claim 1 , further comprising at least two contact pads, each contact pad being electrically coupled to a different portion of the first layer.
7. The thermistor of claim 6 , wherein the contact pads are formed using at least one of: (i) doped silicon carbide, (ii) nickel, (iii) gold, (iv) conductive carbon, (v) platinum, or (vi) tungsten.
8. The thermistor of claim 1 , wherein the resistor is associated with a negative temperature coefficient device.
9. The thermistor of claim 1 , wherein the second layer is to passivate and/or inhibit oxidation of the first layer.
10. The thermistor of claim 1 , wherein the first layer is associated with at least one of (i) a set of resistors connected in series or (ii) a set of resistors connected in parallel.
11. A method, comprising:
flowing current through a resistor comprised of a first layer that comprises wires of doped poly-silicon carbide, wherein a second layer of undoped material is formed on the first layer; and
determining a temperature based on an electrical characteristic of the wires of doped poly-silicon carbide.
12. The method of claim 11 , further comprising:
measuring at least one of the current and a voltage associated with the resistor to determine the electrical characteristic of the wires of doped poly-silicon carbide.
13. The method of claim 11 , wherein the second layer comprises undoped silicon carbide.
14. A method, comprising:
forming wires of doped poly-silicon carbide on a substrate to create a resistor; and
forming a layer of undoped material on the wires of doped poly-silicon carbide to protect the resistor.
15. The method of claim 14 , wherein the wires of doped poly-silicon carbide are formed via a low pressure chemical vapor deposition process.
16. The method of claim 14 , wherein the layer of undoped material comprises a layer of undoped silicon carbide.
17. The method of claim 14 , wherein the wires of doped poly-silicon carbide are formed between the layer of undoped material and a second layer of undoped material.