HIGH-SENSITIVITY SILICON CARBIDE INTEGRATABLE TEMPERATURE SENSOR

Abstract

The invention relates to a high-sensitivity silicon carbide integratable temperature sensor. Voltage drops of an N-type silicon carbide conductor and a P-type silicon carbide semiconductor of the temperature sensor are a positive temperature coefficient and a negative temperature coefficient respectively, so that the change rate of a difference between the voltage drops of two electrodes with temperature will be increased. The temperature sensor has a wide temperature measurement range and high temperature measurement sensitivity, can be integrated in a silicon carbide power semiconductor alone, and is process-compatible.

Claims

1. A high-sensitivity silicon carbide integratable temperature sensor, comprising a first PAD region (1), a second PAD region (2), a third PAD region (3), a P-type well region (4), an N-type well region (5), a first metal (6), a second metal (7), a third metal (8), a first ohmic contact region (9), a second ohmic contact region (10), and a third ohmic contact region (11); the N-type well region (5) and the second ohmic contact region (10) are located in the P-type well region (4) in a spaced manner; the first ohmic contact region (9) is located in the N-type well region (5); the third ohmic contact region (11) is located in the P-type well region (4), and is connected to the P-type well region (4) and the N-type well region (5); the third ohmic contact region (11) extends from the first metal (6) into the first PAD region (1), the first ohmic contact region (9) extends from the second metal (7) into the second PAD region (2), and the second ohmic contact region (10) extends from the third metal (8) into the third PAD region (3); a first electrode formed by the first PAD region is connected to the P-type well region (4) and the N-type well region (5), a second electrode formed by the second PAD region is connected to the N-type well region (5), and a third electrode formed by the third PAD region is connected to the P-type region (4); when currents are applied to the second electrode and third electrode respectively, a voltage difference between the second electrode and the third electrode is in an approximately linear relationship with temperature, and is tested through fitting calibration to represent an operating temperature of a device.

2. The high-sensitivity silicon carbide integratable temperature sensor according to claim 1, wherein the P-type well region (4) is formed by aluminum ion implantation.

3. The high-sensitivity silicon carbide integratable temperature sensor according to claim 1, wherein the N-type well region (5) is formed by phosphorous ion implantation.

4. The high-sensitivity silicon carbide integratable temperature sensor according to claim 1, wherein a doping concentration of the P-type well region (4) is from 1e15 cm-3 to 1e20 cm-3, and/or, a doping concentration of the N-type well region (5) is from 1e15 cm-3 to 1e19 cm-3.

5. The high-sensitivity silicon carbide integratable temperature sensor according to claim 1, wherein an implantation depth of the P-type well region (4) is greater than that of the N-type well region 5.

6. The high-sensitivity silicon carbide integratable temperature sensor according to claim 1, wherein the second ohmic contact region (10) is formed by ion implantation the same as that of the P-type well region (4).

7. The high-sensitivity silicon carbide integratable temperature sensor according to claim 1, wherein a doping concentration of the second ohmic contact region (10) is from 1e18 cm-3 to 1e21 cm-3.

8. The high-sensitivity silicon carbide integratable temperature sensor according to claim 1, wherein the first ohmic contact region (9) is formed by ion implantation the same as that of the N-type well region 5.

9. The high-sensitivity silicon carbide integratable temperature sensor according to claim 1, wherein a doping concentration of the first ohmic contact region (9) is from 1e18 cm-3 to 1e22 cm-3.

10. The high-sensitivity silicon carbide integratable temperature sensor according to claim 1, wherein the first metal (6), the second metal (7) and the third metal (8) are aluminum.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0024] FIG. 1 is a structural view of a high-sensitivity silicon carbide integratable temperature sensor according to one embodiment of the invention;

[0025] FIG. 2 is a structural view of well regions of the high-sensitivity silicon carbide integratable temperature sensor according to one embodiment of the invention;

[0026] FIG. 3 is a sectional view of a well region drawn along section line AA′ in FIG. 2;

[0027] FIG. 4 is a sectional view of a well region drawn along section line BB′ in FIG. 2;

[0028] FIG. 5 is an equivalent circuit diagram, namely a temperature measurement diagram, of the high-sensitivity silicon carbide integratable temperature sensor according to one embodiment of the invention.

[0029] Components represented by the reference signs in the figures:

[0030] 1, first PAD region; 2, second PAD region; 3, third PAD region; 4, P-type well region; 5, N-type well region; 6, first metal; 7, second metal; 8, third metal; 9, first ohmic contact region; 10, second ohmic contact region; 11, third ohmic contact region.

DETAILED DESCRIPTION OF THE INVENTION

[0031] The principle and features of the invention will be described below in conjunction with the accompanying drawings. The embodiments illustrated below are merely used to explain the invention, and are not used to limit the scope of the invention.

[0032] As shown in FIG. 1-FIG. 4, a first embodiment of the invention provides a high-sensitivity silicon carbide integratable temperature sensor, comprising a first PAD region 1, a second PAD region 2, a third PAD region 3, a P-type well region 4, an N-type well region 5, a first metal 6, a second metal 7, a third metal 8, a first ohmic contact region 9, a second ohmic contact region 10, and a third ohmic contact region 11;

[0033] The N-type well region 5 and the second ohmic contact region 10 are located in the P-type well region 4 in a spaced manner; the first ohmic contact region 9 is located in the N-type well region 5; the third ohmic contact region 11 is located in the P-type well region 4, and is connected to the P-type well region 4 and the N-type well region 5;

[0034] The third ohmic contact region 11 extends from the first metal 6 into the first PAD region 1, the first ohmic contact region 9 extends from the second metal 7 into the second PAD region 2, and the second ohmic contact region 10 extends from the third metal 8 into the third PAD region 3.

[0035] The working principle of the invention is as follows:

[0036] As shown in FIG. 5 which is an equivalent circuit diagram of the temperature sensor, when a constant small current I1 is applied to the second PAD region 2, N-type silicon carbide generates a voltage drop V1; when a constant small current I1 is applied to the third PAD region 3, P-type silicon carbide generates a voltage drop V2. Because the lattice scattering of the N-type silicon carbide will be aggravated with the increase of temperature, the migration rate will decrease, the resistance will increase, and V1 will increase with the increase of temperature.

[0037] In addition, impurities in the P-type silicon carbide will not be completely ionized at room temperature, the effective doping concentration of the P-type silicon carbide will be increased by the ionized impurities with the increase of temperature, the resistance will decrease, and V2 will decrease with the increase of temperature.

[0038] If the change rate of V1 with temperature is S1, S1=dV 1/dT, and S1 is positive. If the change rate of V2 with temperature is S2, S2=dV 2/dT, and S2 is negative. By testing the voltage across two terminals of a port 1 and a port 2, it can be obtained that V=V1−V2, the potential difference is in an approximately linear relationship with the temperature T. The operating temperature of the device can be obtained according to a fitting formula T=a*V+b after fitting calibration, where a and b are fitting parameters. The sensitivity of the temperature sensor meets S=dV/dT=S1−S2=|S1|+|S2|, and is the sum of the sensitivity of two semiconductor regions.

[0039] Optionally, the P-type well region 4 is formed by aluminum ion implantation.

[0040] Optionally, the N-type well region 5 is formed by phosphorous ion implantation.

[0041] Optionally, a doping concentration of the P-type well region 4 is from 1e15 cm-3 to 1e20 cm-3, and/or, a doping concentration of the N-type well region 5 is from 1e15 cm-3 to 1e19 cm-3.

[0042] Optionally, an implantation depth of the P-type well region 4 is greater than that of the N-type well region 5.

[0043] Optionally, the second ohmic contact region 10 is formed by ion implantation the same as that of the P-type well region 4.

[0044] Optionally, the second ohmic contact region 10 is formed by ion implantation the same as that of the P-type well region 4.

[0045] Optionally, the first ohmic contact region 9 is formed by ion implantation the same as that of the N-type well region 5.

[0046] Optionally, a doping concentration of the first ohmic contact region 9 is from 1e18 cm-3 to 1e22 cm-3.

[0047] Optionally, the first metal 6, the second metal 7 and the third metal 8 are aluminum.

[0048] The temperature sensor of the invention is provided with three electrodes, wherein a first electrode formed by the first PAD region covers the P-type region and the N-type region, a second electrode formed by the second PAD region is connected to the P-type region, and a third electrode formed by the third PAD region is connected to the N-type region. The first electrode of the temperature sensor is generally in short connection with a source or cathode of a main device, and when a small current is applied to the second electrode and the third electrode, a voltage difference between the second electrode and the third electrode is in an approximately linear relationship, and the operating temperature of a device can be represented by testing the voltage difference between the second electrode and the third electrode through fitting calibration. Because a voltage drop of the N-type silicon carbide semiconductor is a positive temperature coefficient and a voltage drop of the P-type silicon carbide semiconductor is a negative temperature coefficient, the change rate of a difference between the voltage drops of two electrodes with temperature will be increased. The temperature sensor has a wide temperature measurement range and high temperature measurement sensitivity, can be integrated in a silicon carbide power semiconductor alone, and is process-compatible. According to the temperature sensor, a P-type region is electrically isolated from a main device, so that the working state of the temperature sensor and the working state of the main device will not be affected by each other. In addition, the current of the P-type or N-type semiconductor is small, so that a mutual influence of the current in the N-type semiconductor and the current in the P-type semiconductor is avoided.

[0049] In the drawings of the invention, grid lines corresponding to different components are merely used to distinguish different components, and do not have any structural meanings.

[0050] In the description of the invention, terms such as “first” and “second” are merely used for a descriptive purpose, and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features referred to. Therefore, a feature defined by “first” or second” may explicitly or implicitly indicate the inclusion of at least one said feature. In the description of the invention, “multiple” refers to at least two, such as three, unless otherwise specifically and clearly defined.

[0051] In the description of the invention, the description of the reference terms such as “one embodiment”, “some embodiments”, “example”, “specific example”, and “some examples” indicates that the specific characteristics, structures, materials or features described in conjunction with the embodiment or example are included in at least one embodiment or example of the invention. In this specification, illustrative descriptions of these terms do not necessarily refer to identical embodiments or examples. In addition, the specific characteristics, structures, materials or features in the description may be combined properly in one or more embodiments or examples. Moreover, those skilled in the art may integrate or combine different embodiments or examples described in this specification, or the features of different embodiments or examples without mutual contradiction.

[0052] The foregoing description is merely used to explain preferred embodiments of the invention, and is not used to limit the invention. Any amendments, equivalent substitutions and improvements made based on the spirit and principle of the invention should fall within the protection scope of the invention.