Lossless mercury probe testing device

Abstract

According to the nondestructive mercury probe testing device, a sample table is provided with an upper surface and a lower surface which are used for adsorbing a semiconductor to be tested in a vacuum mode, an air inlet hole penetrates through the sample table and extends to a first mercury bottle and a second mercury bottle respectively, so that the first mercury bottle and the second mercury bottle are communicated with the atmosphere, and a point electrode contact hole is formed in the upper surface and is covered by the semiconductor to be tested. The C-type electrode contact groove is arranged on the upper surface and is covered by a semiconductor to be detected, the vacuum pumping hole is arranged on the sample table and extends into the liquid collection bottle for vacuumizing, the vacuum pumping hole is used for vacuumizing, and first liquid mercury in the first mercury bottle enters the point electrode contact hole connecting hole through the first metal connecting pipe so as to fill the point electrode contact hole and be in contact with the semiconductor to be detected; second liquid mercury in the second mercury bottle enters the C-type electrode contact groove connecting hole through the second metal connecting pipe so as to fill the C-type electrode contact groove and make contact with the semiconductor to be tested. The CV tester is connected with the first signal outgoing line and the second signal outgoing line so as to measure a CV curve.

Description

Technical Field

[0001] The invention relates to the technical field of nondestructive testing of semiconductor carrier concentration, in particular to a nondestructive mercury probe testing device. Background Art

[0002] The doping concentration determines the equilibrium carrier concentration inside the semiconductor, which in turn affects the performance of the semiconductor and is one of its most important parameters. A stable doping concentration can ensure the successful preparation of the device. At present, the main test methods for the carrier concentration inside the semiconductor include Hall test, probe IV method, CV method, etc. Compared with the other two methods, the CV method can obtain the change of carrier concentration with depth, which is very important for device preparation. The principle is to reverse bias the PN junction or Schottky junction by applying voltage, and the depletion layer thickness will increase with the increase of the reverse bias voltage. In addition to being related to the voltage, its thickness is also related to the carrier concentration. Through the CV test, the distribution of the doping concentration in the depth direction can be calculated.

[0003] When the PN junction is reverse biased, depletion will occur on both sides of the P-type semiconductor and the N-type semiconductor, and the analysis and calculation are relatively complicated. However, the depletion of the Schottky junction can only occur on one side of the semiconductor, and the accuracy of the test carrier concentration is higher. Therefore, this method is currently a commonly used semiconductor carrier concentration test method.

[0004] However, the preparation of Schottky diodes containing ohmic contact metal electrodes not only takes a long period of time, but also the ohmic contact annealing is an irreversible process, which is not suitable for online non-destructive testing. The advantages of the double mercury probe carrier test method in the prior art are high accuracy, wide application range, and non-destructive and fast. The disadvantage is that the contact area of ​​the mercury probe electrode is difficult to control, which directly affects the test results, and the mercury exposed in the air is easily oxidized, which will affect the environment and operators.

[0005] The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0006] In view of the shortcomings or defects of the prior art, a non-destructive mercury probe testing device is provided, which solves the problems of unstable mercury electrode, difficult to control contact area, easy overflow, etc. during the mercury probe measurement process. The device can stably maintain the contact area of ​​the mercury electrode, reduce the contact area of ​​the mercury electrode with the air, and significantly improve the measurement stability and test efficiency.

[0007] The purpose of the present invention is achieved through the following technical solutions.

[0008] A non-destructive mercury probe testing device comprises: A sample stage having an upper surface for vacuum adsorbing the semiconductor to be tested and a lower surface opposite to the upper surface, a first metal electrode block, which is sealingly fixed to the lower surface, A first signal lead-out line is fixedly connected to the first metal electrode block via a first signal line fixing bolt. a second metal electrode block, which is sealingly fixed to the lower surface, A second signal lead-out line is fixedly connected to the second metal electrode block via a second signal line fixing bolt. a first mercury bottle, which is detachably connected to the first metal electrode block, and contains first liquid mercury; a second mercury bottle, which is detachably connected to the second metal electrode block, and contains second liquid mercury; A first metal electrode extension rod extends from the first metal electrode block into the first mercury bottle and is immersed in the first liquid mercury. A second metal electrode extension rod extends from the second metal electrode block into the second mercury bottle and is immersed in the second liquid mercury. The air inlet hole is provided on the sample stage and extends to the first mercury bottle and the second mercury bottle respectively, so that the first mercury bottle and the second mercury bottle are connected to the atmosphere. a point electrode contact hole, which is provided on the upper surface and covered by the semiconductor to be tested, a point electrode contact hole connecting hole, which is connected to the point electrode contact hole and extends in the sample stage, A first metal connecting tube, one end of which is connected to the point electrode contact hole connecting hole, and the other end of which extends into the first mercury bottle and is immersed in the first liquid mercury, A C-shaped electrode contact groove is provided on the upper surface and is covered by the semiconductor to be tested, A C-shaped electrode contact groove connecting hole is connected to the C-shaped electrode contact groove and extends in the sample stage. A second metal connecting tube, one end of which is connected to the C-type electrode contact slot connecting hole, and the other end of which extends into the second mercury bottle and is immersed in the second liquid mercury. an annular vacuum groove, which is provided on the upper surface, an annular vacuum groove connecting hole, which is connected to the annular vacuum groove and extends inside the sample stage, A liquid collecting bottle, which is sealed and connected to the bottom of the sample stage, A flow guide tube, one end of which is connected to the annular vacuum groove connection hole, and the other end of which extends into the liquid collecting bottle, A vacuum evacuation hole is provided on the sample stage and extends into the liquid collection bottle to evacuate the sample. When the vacuum pumping hole is evacuated, the first liquid mercury in the first mercury bottle enters the point electrode contact hole through the first metal connecting tube to fill the point electrode contact hole and contact the semiconductor to be tested, and the second liquid mercury in the second mercury bottle enters the C-type electrode contact groove through the second metal connecting tube to fill the C-type electrode contact groove and contact the semiconductor to be tested. The CV tester is respectively connected to the first signal output line and the second signal output line to measure the CV curve.

[0009] In the nondestructive mercury probe testing device, the first liquid mercury in the point electrode contact hole is connected to the low potential of the CV tester through the first metal electrode block and the first signal connection line, and contacts the semiconductor to achieve reverse bias to form a depletion layer in the semiconductor. The second liquid mercury in the C-type electrode contact groove is connected to the high potential of the CV tester through the second metal electrode block and the second signal connection line, and contacts the semiconductor to achieve forward bias.

[0010] In the non-destructive mercury probe test device, the CV tester calculates the carrier concentration at different depths in the semiconductor by the following formula: , Where N(x) is the carrier concentration, A is the contact area of ​​mercury in the point electrode contact hole 1, ε0 is the vacuum dielectric constant, ε Si is the relative dielectric constant of silicon, C is the capacitance value measured by the CV tester, and V is the reverse bias voltage value measured by the CV tester.

[0011] In the non-destructive mercury probe testing device, a filter is arranged on the liquid collecting bottle to prevent mercury vapor from escaping therefrom.

[0012] In the non-destructive mercury probe testing device, the C-shaped electrode contact groove surrounds the point electrode contact hole, and the annular vacuum groove surrounds the point electrode contact hole and the C-shaped electrode contact groove.

[0013] In the nondestructive mercury probe testing device, the point electrode contact hole connecting hole extends toward the first mercury bottle in the sample stage, and the C-type electrode contact slot connecting hole extends toward the second mercury bottle in the sample stage.

[0014] In the non-destructive mercury probe testing device, the C-type electrode contact slot connecting hole is an obliquely extending hole, and the point electrode contact hole connecting hole is a vertical hole.

[0015] In the non-destructive mercury probe testing device, the first mercury bottle is threadedly connected to the first metal electrode block and sealed via a gasket, and the second mercury bottle is threadedly connected to the second metal electrode block and sealed via a gasket.

[0016] In the non-destructive mercury probe testing device, the second metal electrode block is spaced apart from and arranged side by side with the first metal electrode block, and the first metal electrode block and the second metal electrode block are both recessed on the sample stage and have their bottoms flush with the lower surface.

[0017] In the non-destructive mercury probe testing device, the upper surface is a frosted surface that maintains a level surface, and the surface roughness is between 1um and 200um to ensure the vacuum degree of the point electrode contact hole and the C-type electrode contact groove while preventing mercury from being sucked out.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention can realize non-destructive rapid testing of semiconductor materials, ensure the stability of the contact area, improve the accuracy of repeated measurements, avoid mercury overflow by adding a liquid collecting bottle and rear-end filtering, and significantly improve test safety.

[0019] The above description is only an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and to achieve the extent that those skilled in the art can implement it according to the contents of the specification, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are exemplified below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0021] In the attached picture: Figure 1 A side view schematic diagram of a non-destructive mercury probe testing device provided by one embodiment of the present invention; Figure 2 A schematic top view of the center of a sample stage of a non-destructive mercury probe testing device provided by one embodiment of the present invention; Figure 3 A schematic side view of an electrode portion after contact with vacuum adsorbed mercury in a non-destructive mercury probe testing device provided by an embodiment of the present invention; Figure 4 A schematic diagram of vacuum mercury electrode contact of a non-destructive mercury probe testing device provided by one embodiment of the present invention; Figure 5A test connection schematic diagram of a non-destructive mercury probe test device provided by one embodiment of the present invention; Figure 6 A schematic diagram of a CV curve of a SiC epitaxial wafer of a non-destructive mercury probe testing device provided by an embodiment of the present invention; Figure 7 A non-destructive mercury probe testing device according to an embodiment of the present invention is provided. 2 -V curve diagram; Figure 8 A schematic diagram of doping concentrations at different depths of a silicon carbide epitaxial wafer of a non-destructive mercury probe testing device provided by an embodiment of the present invention.

[0022] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0024] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0025] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0026] For a better understanding, Figures 1 to 8 As shown, a non-destructive mercury probe testing device comprises: The sample stage 6 has an upper surface for vacuum adsorbing the semiconductor to be tested and a lower surface opposite to the upper surface, A first metal electrode block 13 is sealed and fixed to the lower surface. The first signal lead-out line 15 is fixedly connected to the first metal electrode block 13 via a first signal line fixing bolt 17. A second metal electrode block 14 is sealed and fixed to the lower surface, The second signal lead-out line 16 is fixedly connected to the second metal electrode block 14 via a second signal line fixing bolt 18. A first mercury bottle 8 is detachably connected to the first metal electrode block 13, and contains first liquid mercury 20. The second mercury bottle 7 is detachably connected to the second metal electrode block 14, and contains second liquid mercury 19. A first metal electrode extension rod 11 extends from the first metal electrode block 13 into the first mercury bottle 8 and is immersed in the first liquid mercury 20. The second metal electrode extension rod 12 extends from the second metal electrode block 14 into the second mercury bottle 7 and is immersed in the second liquid mercury 19. The air inlet 5 is provided through the sample stage 6 and extends to the first mercury bottle 8 and the second mercury bottle 7 respectively, so that the first mercury bottle 8 and the second mercury bottle 7 are connected to the atmosphere. A point electrode contact hole 1, which is provided on the upper surface and covered by the semiconductor to be tested, The point electrode contact hole connecting hole 21 is connected to the point electrode contact hole 1 and extends in the sample stage 6. The first metal connecting tube 10 has one end connected to the point electrode contact hole connecting hole 21, and the other end extending into the first mercury bottle 8 and immersed in the first liquid mercury 20. A C-shaped electrode contact groove 2 is provided on the upper surface and is covered by the semiconductor to be tested, The C-type electrode contact groove connecting hole 22 is connected to the C-type electrode contact groove 2 and extends in the sample stage 6. The second metal connecting tube 9 has one end connected to the C-type electrode contact slot connecting hole 22, and the other end extending into the second mercury bottle 7 and immersed in the second liquid mercury 19. an annular vacuum groove 3, which is provided on the upper surface, an annular vacuum groove connecting hole 4, which is connected to the annular vacuum groove 3 and extends inside the sample stage 6, The liquid collecting bottle 23 is sealed and connected to the bottom of the sample stage 6. The flow guide tube 24 has one end connected to the annular vacuum tank connection hole 4 and the other end extending into the liquid collecting bottle 23. A vacuum evacuation hole 26 is provided on the sample stage 6 and extends into the liquid collecting bottle 23 to evacuate the sample. When the vacuum pumping hole 26 is evacuated, the first liquid mercury 20 in the first mercury bottle 8 enters the point electrode contact hole connection hole 21 through the first metal connecting tube 10 to fill the point electrode contact hole 1 and contact the semiconductor to be tested, and the second liquid mercury 19 in the second mercury bottle 7 enters the C-type electrode contact groove connection hole 22 through the second metal connecting tube 9 to fill the C-type electrode contact groove 2 and contact the semiconductor to be tested. The CV tester is respectively connected to the first signal output line 15 and the second signal output line 16 to measure the CV curve.

[0027] In a preferred embodiment of the nondestructive mercury probe testing device, the first liquid mercury 20 in the point electrode contact hole 1 is connected to the low potential of the CV tester through the first metal electrode block 13 and the first signal connection line 15, and contacts the semiconductor to achieve reverse bias to form a depletion layer in the semiconductor. The second liquid mercury 19 in the C-type electrode contact groove 2 is connected to the high potential of the CV tester through the second metal electrode block 14 and the second signal connection line 16, and contacts the semiconductor to achieve forward bias.

[0028] In a preferred embodiment of the non-destructive mercury probe test device, the CV tester calculates the carrier concentration at different depths in the semiconductor by the following formula: , Where N(x) is the carrier concentration, A is the contact area of ​​mercury in the point electrode contact hole 1, ε0 is the vacuum dielectric constant, ε Si is the relative dielectric constant of silicon, C is the capacitance value measured by the CV tester, and V is the reverse bias voltage value measured by the CV tester.

[0029] In a preferred embodiment of the non-destructive mercury probe testing device, a filter 25 is disposed on the liquid collecting bottle 23 to prevent mercury vapor from escaping therefrom.

[0030] In a preferred embodiment of the non-destructive mercury probe testing device, the C-shaped electrode contact groove 2 surrounds the point electrode contact hole 1 , and the annular vacuum groove 3 surrounds the point electrode contact hole 1 and the C-shaped electrode contact groove 2 .

[0031] In a preferred embodiment of the nondestructive mercury probe testing device, the point electrode contact hole connecting hole 21 extends in the sample stage 6 toward the first mercury bottle 8 , and the C-type electrode contact slot connecting hole 22 extends in the sample stage 6 toward the second mercury bottle 7 .

[0032] In a preferred embodiment of the non-destructive mercury probe testing device, the C-type electrode contact slot connecting hole 22 is an obliquely extending hole, and the point electrode contact hole connecting hole 21 is a vertical hole.

[0033] In a preferred embodiment of the non-destructive mercury probe testing device, the first mercury bottle 8 is threadedly connected to the first metal electrode block 13 and sealed via a gasket, and the second mercury bottle 7 is threadedly connected to the second metal electrode block 14 and sealed via a gasket.

[0034] In a preferred embodiment of the non-destructive mercury probe testing device, the second metal electrode block 14 is spaced apart from and arranged side by side with the first metal electrode block 13 , and the first metal electrode block 13 and the second metal electrode block 14 are both recessed in the sample stage 6 and their bottoms are flush with the lower surface.

[0035] In a preferred embodiment of the non-destructive mercury probe testing device, the upper surface is a horizontal frosted surface with a surface roughness between 1um and 200um to ensure the vacuum degree of the point electrode contact hole 1 and the C-type electrode contact groove 2. At the same time, due to the large surface tension of mercury, mercury is prevented from being sucked out of the gap.

[0036] In one embodiment, the first liquid mercury 20 in the point electrode contact hole 1 is connected to the negative voltage high potential, i.e., the Hp and Hc ports of the CV tester, through the first signal connection line 15, to form a depletion layer in the semiconductor, and the second liquid mercury 19 in the C-type electrode contact groove 2 is grounded through the second signal connection line 16, and contacts the semiconductor to achieve forward bias, and the capacitance value in the test loop is 0, which is equivalent to an ohmic contact. Figure 5 shown.

[0037] In another embodiment, the area of ​​the point electrode contact hole 1 is much smaller than the area of ​​the C-type electrode contact groove 2 to ensure the accuracy of the test, the point electrode contact hole 1 is a Schottky contact circular electrode groove, and the area of ​​the C-type electrode contact groove 2 is a Schottky contact C-type electrode groove. The area ratio of the point electrode contact hole 1 to the C-type electrode contact groove 2 is less than 0.02 to reduce the resistance introduced by the forward Schottky during the test, thereby ensuring the accuracy of the CV test.

[0038] In another embodiment, the first liquid mercury 20 and the second liquid mercury 19 filled in the point electrode contact hole 1 and the C-type electrode contact groove 2 are in contact with the mercury in the first mercury bottle 8 and the second mercury bottle 7 through the first metal tube and the second metal tube, respectively, to reduce the connection resistance.

[0039] In another embodiment, the first metal electrode block 13 is connected to the first liquid mercury 20 in the first mercury bottle 8 through a semi-annular first metal tube.

[0040] In another embodiment, the first metal electrode block 13 fixes the shielded cable by means of fixing bolts to achieve the introduction and extraction of the test signal.

[0041] In another embodiment, the shape and area of ​​mercury contact are controlled by the pressure provided by the vacuum exhaust hole 26, and the air inlet 5 connects the first mercury bottle 8 and the second mercury bottle 7 to the atmosphere to ensure that the pressure inside the first mercury bottle 8 and the second mercury bottle 7 is atmospheric pressure.

[0042] In another embodiment, the mercury sucked into the annular vacuum groove 3 due to improper operation will be collected in the liquid collecting bottle 23 to prevent the mercury from overflowing.

[0043] In one embodiment, a filter layer is provided above the liquid collecting bottle 23 to prevent the mercury vapor from being sucked out.

[0044] In one embodiment, the semiconductor material is placed on the sample stage 6 and a certain pressure is applied to ensure the vacuum degree of the point electrode contact hole 1 and the C-type electrode contact groove 2 .

[0045] In one embodiment, a non-destructive mercury probe testing apparatus comprises, A sample stage 6, which has an upper surface for vacuum adsorbing the semiconductor to be tested and a lower surface relative to the upper surface, and further, the upper surface is kept horizontal; A first metal electrode block 13 is sealed and fixed to the lower surface. The first signal lead-out line 15 is fixedly connected to the first metal electrode block 13 via a first signal line fixing bolt 17. A second metal electrode block 14 is sealed and fixed to the lower surface. Further, the second metal electrode block 14 is spaced apart from and arranged side by side with the first metal electrode block 13. Further, both the first metal electrode block 13 and the second metal electrode block 14 are recessed on the sample stage 6 and their bottoms are flush with the lower surface. The second signal lead-out line 16 is fixedly connected to the second metal electrode block 14 via a second signal line fixing bolt 18. The first mercury bottle 8 is detachably connected to the first metal electrode block 13, and the first mercury bottle 8 contains first liquid mercury 20. Furthermore, the first mercury bottle 8 is threadedly connected to the first metal electrode block 13 and sealed via a gasket. The second mercury bottle 7 is detachably connected to the second metal electrode block 14, and contains second liquid mercury 19. Furthermore, the second mercury bottle 7 is threadedly connected to the second metal electrode block 14 and sealed via a gasket. A first metal electrode extension rod 11 extends from the first metal electrode block 13 into the first mercury bottle 8 and is immersed in the first liquid mercury 20. The second metal electrode extension rod 12 extends from the second metal electrode block 14 into the second mercury bottle 7 and is immersed in the second liquid mercury 19. The air inlet 5 is provided through the sample stage 6 and extends to the first mercury bottle 8 and the second mercury bottle 7 respectively, so that the first mercury bottle 8 and the second mercury bottle 7 are connected to the atmosphere. A point electrode contact hole 1, which is provided on the upper surface and covered by the semiconductor to be tested, The point electrode contact hole connecting hole 21 is connected to the point electrode contact hole 1 and extends in the sample stage 6. Furthermore, the point electrode contact hole connecting hole 21 extends in the sample stage 6 toward the first mercury bottle 8. The first metal connecting tube 10 has one end connected to the point electrode contact hole connecting hole 21, and the other end extending into the first mercury bottle 8 and immersed in the first liquid mercury 20. A C-shaped electrode contact groove 2 is provided on the upper surface and is covered by the semiconductor to be tested, The C-type electrode contact groove connection hole 22 is connected to the C-type electrode contact groove 2 and extends in the sample stage 6. Further, the C-type electrode contact groove connection hole 22 extends in the sample stage 6 toward the second mercury bottle 7. Further, the C-type electrode contact groove connection hole 22 is an inclined extending hole, and the point electrode contact hole connection hole 21 is a vertical hole. The second metal connecting tube 9 has one end connected to the C-type electrode contact slot connecting hole 22, and the other end extending into the second mercury bottle 7 and immersed in the second liquid mercury 19. an annular vacuum groove 3, which is arranged on the upper surface and covered by the semiconductor to be tested, further, the C-type electrode contact groove 2 surrounds the point electrode contact hole 1, further, the annular vacuum groove 3 surrounds the point electrode contact hole 1 and the C-type electrode contact groove 2, an annular vacuum groove connecting hole 4, which is connected to the annular vacuum groove 3 and extends inside the sample stage 6, The liquid collecting bottle 23 is sealed and connected to the bottom of the sample stage 6. The flow guide tube 24 has one end connected to the annular vacuum tank connection hole 4 and the other end extending into the liquid collecting bottle 23. The filter 25 is provided on the liquid collecting bottle 23 to prevent the mercury vapor from escaping. A vacuum evacuation hole 26 is provided on the sample stage 6 and extends into the liquid collecting bottle 23 to evacuate the sample. When the vacuum exhaust hole 26 is evacuated, the first liquid mercury 20 in the first mercury bottle 8 enters the point electrode contact hole connection hole 21 through the first metal connecting tube 10 to fill the point electrode contact hole 1 and contact the semiconductor to be tested. The first liquid mercury 20 in the point electrode contact hole 1 is connected to a low potential through the first metal electrode block 13 and the first signal connection line 15, and contacts the semiconductor to achieve reverse bias to form a depletion layer in the semiconductor. The second liquid mercury 19 in the second mercury bottle 7 enters the C-type electrode contact groove connection hole 22 through the second metal connecting tube 9 to fill the C-type electrode contact groove 2 and contact the semiconductor to be tested. The second liquid mercury 19 in the C-type electrode contact groove 2 is connected to a high potential through the second metal electrode block 14 and the second signal connection line 16, and contacts the semiconductor to achieve forward bias. The CV tester is respectively connected to the first signal output line 15 and the second signal output line 16 to measure the CV curve.

[0046] During the test, the wafer is placed on the sample stage 6 with the measuring surface facing downward and a certain pressure is applied. Through vacuuming, the mercury will be drawn out and contact the surface of the wafer. The frosted surface sample stage 6 of the test device can ensure the vacuum degree at the gap to maintain the shape of the mercury probe. The mercury metal will not overflow due to the existence of surface tension. Figure 3 As shown. In addition, a liquid collecting bottle 23 is connected in series on the vacuum pipe to store mercury drops that overflow due to improper operation to ensure the safety of the test. Furthermore, the "double vacuum system" of the present invention can use vacuum suction to suck out the mercury in the mercury bottle through the connecting pipe to achieve contact with the sample (semiconductor material). The rough surface of the sample stage 6 ensures the transmission of vacuum. At the same time, due to the surface tension of mercury, mercury cannot be sucked away by vacuum under normal circumstances. After the surface tension and vacuum suction reach a balance, the mercury will maintain a certain shape, ensuring the stability of the electrode contact area. The double vacuum system specifically refers to the two Schottky contacts in the test structure, both of which use a vacuum method to suck out mercury to achieve contact with the semiconductor material; in addition, the shape and contact area of ​​the contact mercury are related to the vacuum pressure, which is usually controlled at 20-40kPa, so that the contact area does not change much. Too small a vacuum value is not enough to bring the mercury into contact with the sample, and too large a vacuum degree can easily suck away the mercury. After the vacuum is removed, the mercury will automatically return to the mercury bottle due to gravity, thus achieving contact between the semiconductor material and the mercury electrode. By applying high and low potentials, the CV curve is obtained, and further calculations can be used to obtain a non-destructive and rapid test of the carrier concentration in the semiconductor.

[0047] Figures 6 to 8 The data of SiC epitaxial wafers through mercury probe, Figure 6 A schematic diagram of a CV curve of a SiC epitaxial wafer of a non-destructive mercury probe testing device provided by an embodiment of the present invention, Figure 7 A non-destructive mercury probe testing device according to an embodiment of the present invention is provided. 2-V curve diagram, Figure 8 A schematic diagram of the doping concentration of a silicon carbide epitaxial wafer at different depths of a non-destructive mercury probe test device provided by an embodiment of the present invention. The doping concentration of the epitaxial wafer is calculated to be between 1e16-2e16cm -3 The test accuracy is higher.

[0048] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0049] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A non-destructive mercury probe testing device, characterized in that: These include, A sample stage having an upper surface for vacuum adsorbing the semiconductor to be tested and a lower surface opposite to the upper surface, a first metal electrode block, which is sealingly fixed to the lower surface, A first signal lead-out line is fixedly connected to the first metal electrode block via a first signal line fixing bolt. a second metal electrode block, which is sealingly fixed to the lower surface, A second signal lead-out line is fixedly connected to the second metal electrode block via a second signal line fixing bolt. a first mercury bottle, which is detachably connected to the first metal electrode block, and contains first liquid mercury; a second mercury bottle, which is detachably connected to the second metal electrode block, and contains second liquid mercury; A first metal electrode extension rod extends from the first metal electrode block into the first mercury bottle and is immersed in the first liquid mercury. A second metal electrode extension rod extends from the second metal electrode block into the second mercury bottle and is immersed in the second liquid mercury. The air inlet hole is provided on the sample stage and extends to the first mercury bottle and the second mercury bottle respectively, so that the first mercury bottle and the second mercury bottle are connected to the atmosphere. a point electrode contact hole, which is provided on the upper surface and covered by the semiconductor to be tested, a point electrode contact hole connecting hole, which is connected to the point electrode contact hole and extends in the sample stage, A first metal connecting tube, one end of which is connected to the point electrode contact hole connecting hole, and the other end of which extends into the first mercury bottle and is immersed in the first liquid mercury, A C-shaped electrode contact groove is provided on the upper surface, A C-shaped electrode contact groove connecting hole is connected to the C-shaped electrode contact groove and extends in the sample stage. A second metal connecting tube, one end of which is connected to the C-type electrode contact slot connecting hole, and the other end of which extends into the second mercury bottle and is immersed in the second liquid mercury. an annular vacuum groove, which is arranged on the upper surface and covered by the semiconductor to be tested, an annular vacuum groove connecting hole, which is connected to the annular vacuum groove and extends inside the sample stage, A liquid collecting bottle, which is sealed and connected to the bottom of the sample stage, A flow guide tube, one end of which is connected to the annular vacuum groove connection hole, and the other end of which extends into the liquid collecting bottle, A vacuum evacuation hole is provided on the sample stage and extends into the liquid collection bottle to evacuate the sample. When the vacuum pumping hole is evacuated, the first liquid mercury in the first mercury bottle enters the point electrode contact hole through the first metal connecting tube to fill the point electrode contact hole and contact the semiconductor to be tested, and the second liquid mercury in the second mercury bottle enters the C-type electrode contact groove through the second metal connecting tube to fill the C-type electrode contact groove and contact the semiconductor to be tested. The CV tester is respectively connected to the first signal output line and the second signal output line to measure the CV curve.

2. The non-destructive mercury probe testing device according to claim 1, characterized in that: Preferably, the first liquid mercury in the point electrode contact hole is connected to the low potential of the CV tester through the first metal electrode block and the first signal connection line, and contacts the semiconductor to achieve reverse bias to form a depletion layer in the semiconductor, and the second liquid mercury in the C-type electrode contact groove is connected to the high potential of the CV tester through the second metal electrode block and the second signal connection line, and contacts the semiconductor to achieve forward bias.

3. The non-destructive mercury probe testing device according to claim 1, characterized in that: The CV tester calculates the carrier concentration at different depths in the semiconductor using the following formula: ， Where N(x) is the carrier concentration, A is the contact area of ​​mercury in the point electrode contact hole 1, ε0 is the vacuum dielectric constant, ε Si is the relative dielectric constant of silicon, C is the capacitance value measured by the CV tester, and V is the reverse bias voltage value measured by the CV tester.

4. The non-destructive mercury probe testing device according to claim 1, characterized in that: A filter is arranged on the liquid collecting bottle to prevent the mercury vapor from escaping therefrom.

5. The non-destructive mercury probe testing device according to claim 1, characterized in that: The C-shaped electrode contact groove surrounds the point electrode contact hole, and the annular vacuum groove surrounds the point electrode contact hole and the C-shaped electrode contact groove.

6. The non-destructive mercury probe testing device according to claim 1, characterized in that: The point electrode contact hole connection hole extends in the sample stage toward the first mercury bottle, and the C-type electrode contact groove connection hole extends in the sample stage toward the second mercury bottle.

7. The non-destructive mercury probe testing device according to claim 1, characterized in that: The C-shaped electrode contact slot connection hole is an obliquely extending hole, and the point electrode contact hole connection hole is a vertical hole.

8. The non-destructive mercury probe testing device according to claim 1, characterized in that: The first mercury bottle is threadedly connected to the first metal electrode block and is sealed via a gasket, and the second mercury bottle is threadedly connected to the second metal electrode block and is sealed via a gasket.

9. The non-destructive mercury probe testing device according to claim 1, characterized in that: The second metal electrode block is spaced apart from the first metal electrode block and arranged side by side. The first metal electrode block and the second metal electrode block are both recessedly disposed on the sample stage and have their bottoms flush with the lower surface.

10. The non-destructive mercury probe testing device according to claim 1, characterized in that: The upper surface is a horizontal frosted surface with a surface roughness between 1um and 200um to ensure the vacuum degree of the point electrode contact hole and the C-type electrode contact groove while preventing mercury from being sucked out.

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