Method for detecting side wall quality of semiconductor based on Schottky contact

Abstract

The invention relates to the field of semiconductors, and discloses a method for detecting the side wall quality of a semiconductor based on Schottky contact, and the method comprises the steps: preparing at least two to-be-detected parts based on Schottky contact; each to-be-detected component comprises a semiconductor substrate with a boss and a Schottky metal layer, and in each to-be-detected component, the Schottky metal layers located on the side walls of the bosses are equal in thickness and unequal in length; collecting the measurement current of each to-be-detected component under the condition that the measurement voltage is applied; the measurement voltages are at least two different voltages; the measurement current is the current flowing through the Schottky metal layer on the side wall of the boss; under the same measurement voltage, according to the length of the Schottky metal layer located on the side wall of the boss and the corresponding measurement current, target current is determined; the target current is the current when the length of the Schottky metal layer located on the side wall of the boss is zero; determining a conduction voltage according to the target current and the corresponding measurement voltage; and evaluating the quality of the side wall of the boss according to the conduction voltage. According to the invention, the quality detection of the side wall can be realized.

Description

Technical Field

[0001] The present application relates to the semiconductor field, and in particular to a method for detecting semiconductor sidewall quality based on Schottky contact. Background Art

[0002] Metal-semiconductor Schottky contacts are often used to evaluate damage introduced to the semiconductor surface by processes such as dry etching. Currently, when detecting damage to the semiconductor surface based on Schottky contacts, the schematic diagram of the Schottky contact detection component used is as follows: Figure 1 and Figure 2 As shown, the component to be detected based on Schottky contact includes a semiconductor substrate 1 with a boss, a dielectric film layer 4, an ohmic metal layer 3 and a Schottky metal layer 2. The boss of the semiconductor substrate is generated by etching. After etching, due to the electron / ion bombardment effect, the deposition of reaction products, and / or the atomic mismatch in the surface area of ​​the semiconductor substrate, a damaged layer is generated in the front surface area (Y) and the side wall area (X) of the semiconductor substrate surface, and the front surface area and the side wall area correspond to the Schottky metal layer.

[0003] By continuously applying voltage between the Schottky metal layer and the ohmic contact layer and collecting the corresponding current, a voltage-current curve is obtained. The on-voltage representing the height of the Schottky barrier is determined according to the voltage-current curve, and then the damage of the front surface area of ​​the semiconductor substrate surface is evaluated according to the magnitude of the on-voltage. The reason for evaluating the front surface area is that the contact area (L×W) between the Schottky metal layer and the front surface area is much larger than the contact area (D×W) with the sidewall area, where L>>D, L is the length of the Schottky metal layer in the front surface area, W is the width of the Schottky metal layer, and D is the height of the boss. However, damage detection of the sidewall area cannot be achieved.

[0004] Therefore, how to solve the above technical problems should be the focus of technical personnel in this field. Summary of the invention

[0005] The purpose of the present application is to provide a method for detecting the quality of semiconductor sidewalls based on Schottky contacts, so as to achieve quality detection of the sidewall region.

[0006] In order to solve the above technical problems, the present application provides a method for detecting the quality of semiconductor sidewalls based on Schottky contact, comprising:

[0007] Prepare at least two components to be detected based on Schottky contact; the components to be detected include a semiconductor substrate with a boss and a Schottky metal layer, and in each of the components to be detected, the Schottky metal layer located on the side wall of the boss has an equal thickness and an unequal length;

[0008] Collecting the measurement current of each of the components to be inspected under the applied measurement voltage; the measurement voltage is at least two different voltages; the measurement current is the current flowing through the Schott metal layer located on the side wall of the boss;

[0009] Under the same measurement voltage, a target current is determined according to the length of the Schott metal layer located on the side wall of the boss and the corresponding measurement current; the target current is the current flowing through the side wall of the boss when the length of the Schott metal layer located on the side wall of the boss is zero;

[0010] Determining a turn-on voltage according to the target current and the corresponding measured voltage;

[0011] The quality of the sidewall of the boss on the semiconductor substrate is evaluated according to the on-voltage.

[0012] Optionally, collecting the measured current of each of the components to be detected under the applied measuring voltage includes:

[0013] Applying the measuring voltage between the Schott metal layer and the Ohmic metal layer located on the upper surface of the boss;

[0014] The measurement current is acquired.

[0015] Optionally, determining the target current according to the length of the Schott metal layer located on the side wall of the boss and the corresponding measured current includes:

[0016] Determining a relationship between a measurement current and a length according to a length of the Schott metal layer located on a side wall of the boss and the corresponding measurement current;

[0017] The target current is determined according to the relationship between the measured current and the length.

[0018] Optionally, the measured current and length relationship is a measured current and length relationship curve or a measured current and length relationship formula.

[0019] Optionally, determining the turn-on voltage according to the target current and the corresponding measured voltage includes:

[0020] Determine a target current and a measured voltage relationship curve according to the target current and the corresponding measured voltage;

[0021] According to the target current and measured voltage relationship curve, the target current is extrapolated to zero to obtain the on-state voltage.

[0022] Optionally, the number of components to be detected is two.

[0023] Optionally, the measurement voltage includes two different voltages.

[0024] Optionally, the material of the Schottky metal layer includes gold, aluminum, tungsten, molybdenum, and copper.

[0025] Optionally, the material of the semiconductor substrate includes indium phosphide, gallium arsenide, silicon, or germanium.

[0026] Optionally, evaluating the quality of the sidewall of the boss on the semiconductor substrate according to the on-voltage includes:

[0027] Determining the conduction voltage range in which the conduction voltage is located according to the relationship between the preset conduction voltage range and the damage level;

[0028] The quality grade of the boss sidewall is determined according to the conduction voltage range.

[0029] The present application provides a method for detecting the quality of semiconductor sidewalls based on Schottky contact, comprising: preparing at least two components to be detected based on Schottky contact; the components to be detected include a semiconductor substrate with a boss and a Schottky metal layer, and in each of the components to be detected, the thickness of the Schottky metal layer located on the side wall of the boss is equal, and the length is unequal; collecting the measurement current of each of the components to be detected under the application of a measurement voltage; the measurement voltage is at least two different voltages; the measurement current is the current flowing through the Schottky metal layer located on the side wall of the boss; under the same measurement voltage, according to the length of the Schottky metal layer located on the side wall of the boss and the corresponding measurement current, determining a target current; the target current is the current flowing through the side wall of the boss when the length of the Schottky metal layer located on the side wall of the boss is zero; determining a turn-on voltage according to the target current and the corresponding measurement voltage; and evaluating the quality of the side wall of the boss on the semiconductor substrate according to the turn-on voltage.

[0030] It can be seen that the detection method in this application prepares multiple components to be detected, and the thickness of the Schottky metal layer at the side wall of the boss in each component to be detected is equal, and the length is not equal. Then, a measurement voltage is applied to the Schottky contact area of ​​the side wall of the boss to collect the measurement current flowing through the side wall of the boss, that is, one length corresponds to one measurement current. Under one measurement voltage, the target current of the boss flowing through the side wall when the length is zero is obtained through multiple groups of lengths and measurement currents, that is, one measurement voltage corresponds to one target current. Then, the on-voltage is obtained based on the measurement voltage and the target current. Since the target current is the current flowing through the side wall of the boss when the length of the Schottky metal layer on the side wall of the boss is zero, the on-voltage represents the Schottky barrier height in the side wall area of ​​the boss, and then the surface quality of the side wall area is detected based on the on-voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a structural schematic diagram of a detection component based on Schottky contact in the related art;

[0033] Figure 2 for Figure 1 A top view of the detection component shown;

[0034] Figure 3 A flow chart of a method for detecting semiconductor sidewall quality based on Schottky contact provided in an embodiment of the present application;

[0035] Figure 4 and Figure 5 A top view of a component to be inspected provided in an embodiment of the present application;

[0036] Figure 6 This is a schematic diagram of applying a measurement voltage to a component to be detected and collecting a measurement current in this embodiment;

[0037] Figure 7 for Figure 4 A curve diagram showing the variation of the measured current of the component to be tested with the measured voltage;

[0038] Figure 8 for Figure 5 A curve diagram showing the variation of the measured current of the component to be tested with the measured voltage;

[0039] Fig. 9 for Figure 4 and Figure 5 A curve diagram showing the measured current of the component to be tested as the measured voltage changes;

[0040] Fig.10 is a curve diagram showing the relationship between the measured current and the length of the Schottky metal layer on the side wall of the boss in this embodiment;

[0041] Fig.11 : is a curve diagram showing the relationship between the target current and the measured voltage in this embodiment. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] As described in the background technology section, currently only the damage of the front surface region of the semiconductor substrate surface based on Schottky contact can be detected, while the damage of the sidewall region cannot be detected.

[0045] In view of this, the present application provides a method for detecting the quality of semiconductor sidewalls based on Schottky contact, please refer to Figure 3 , the method comprising:

[0046] Step S101: preparing at least two components to be detected based on Schottky contact; the components to be detected include a semiconductor substrate with a boss and a Schottky metal layer, and in each of the components to be detected, the Schottky metal layer located on the side wall of the boss has equal thickness and unequal length.

[0047] The structural diagram of the component to be tested is as follows: Figure 1 As shown, in addition to the semiconductor substrate 1 having the protrusion and the Schottky metal layer 2 , it also includes an ohmic metal layer 3 and a dielectric film layer 4 .

[0048] The semiconductor substrate 1 may be an N-type substrate or a P-type substrate, both of which are within the protection scope of the present application.

[0049] The material of the Schottky metal layer 2 includes, but is not limited to, gold, aluminum, tungsten, molybdenum, and copper.

[0050] The material of the semiconductor substrate 1 may be indium phosphide, gallium arsenide, silicon, germanium, or other III-V compound materials or IV semiconductor materials.

[0051] The material of the dielectric film layer 4 may be silicon dioxide, silicon nitride, etc. The material of the ohmic metal layer may be a gold-germanium alloy, or the ohmic metal layer may include a stack of a gold layer, a platinum layer and a titanium layer.

[0052] Each component to be detected can be directly used as it has been prepared, or can be prepared by itself. The process flow of preparing each component to be detected can refer to the relevant technology, and will not be described in detail in this application.

[0053] It should be noted that the number of components to be detected is not limited in the present application and depends on the circumstances. For example, the number of components to be detected is two, three, or four.

[0054] For different components to be inspected, the thickness of the Schott metal layer located on the side wall of the boss is equal, but the length is different. Taking the number of components to be inspected as an example, the top view of the components to be inspected is as follows: Figure 4 and Figure 5 As shown, Figure 4 The thickness of the Schott metal layer located on the side wall of the boss is H, and the length is L1; Figure 5 The thickness of the Schott metal layer located on the side wall of the boss is H, and the length is L2.

[0055] Step S102: collecting the measurement current of each of the components to be inspected under the application of a measurement voltage; the measurement voltage is at least two different voltages; the measurement current is the current flowing through the Schott metal layer located on the side wall of the boss.

[0056] As an implementable method, collecting the measured current of each of the components to be detected under the applied measuring voltage includes:

[0057] Applying the measuring voltage between the Schott metal layer and the Ohmic metal layer located on the upper surface of the boss;

[0058] The measurement current is acquired.

[0059] The schematic diagram of applying a measurement voltage to the component to be detected and collecting a measurement current in this embodiment is as follows: Figure 6 shown.

[0060] It should be noted that the number of measurement voltages is not limited in the present application and depends on the circumstances. For example, the measurement voltages include two, three, or four different voltages.

[0061] Each measurement voltage is applied to each component to be detected. For example, when the applied measurement voltage is V1, for the components to be detected whose Schott metal layer lengths on the side walls of the bosses are L1, L2, ..., Ln, respectively, the corresponding measurement currents collected are I1(1), I2(1), ..., In(1); when the applied measurement voltage is V2, for the components to be detected whose Schott metal layer lengths on the side walls of the bosses are L1 and L2, respectively, the corresponding measurement currents collected are I1(2), I2(2), ..., In(2), and so on. When the applied measurement voltage is Vn, for the components to be detected whose Schott metal layer lengths on the side walls of the bosses are L1 and L2, respectively, the corresponding measurement currents collected are I1(n), I2(n), ..., In(n). That is, under each measurement voltage, the length of the Schott metal layer on the side walls of the bosses corresponds to a measurement current.

[0062] Step S103: Under the same measurement voltage, determine the target current according to the length of the Schott metal layer located on the side wall of the boss and the corresponding measurement current; the target current is the current flowing through the side wall of the boss when the length of the Schott metal layer located on the side wall of the boss is zero.

[0063] As an implementable embodiment, determining the target current according to the length of the Schott metal layer located on the side wall of the boss and the corresponding measured current includes:

[0064] Step S1031: determining a relationship between a measurement current and a length according to a length of the Schott metal layer located on a side wall of the boss and the corresponding measurement current.

[0065] The relationship between the measured current and the length includes but is not limited to a curve of the relationship between the measured current and the length or a formula of the relationship between the measured current and the length.

[0066] For example, when the applied measuring voltage is V1, a measuring current and length relationship can be determined according to (L1, I1(1)), (L2, I2(1)), …, (Ln, In(1)); when the applied measuring voltage is V2, a measuring current and length relationship can be determined according to (L1, I1(2)), (L2, I2(2)), …, (Ln, In(2)); when the applied measuring voltage is Vn, a measuring current and length relationship can be determined according to (L1, I1(n)), (L2, I2(n)), …, (Ln, In(n)).

[0067] Step S1032: Determine the target current according to the relationship between the measured current and the length.

[0068] According to the relationship between each measured current and length, a target current I0 can be determined, so one measured voltage corresponds to one target current. For example, when the applied measured voltage is V1, the corresponding target current is I0(1), when the applied measured voltage is V2, the corresponding target current is I0(2), and so on. When the applied measured voltage is Vn, the corresponding target current is I0(n).

[0069] Step S104: determining a turn-on voltage according to the target current and the corresponding measured voltage.

[0070] As an implementable embodiment, determining the turn-on voltage according to the target current and the corresponding measured voltage includes:

[0071] Step S1041: determining a target current and measurement voltage relationship curve according to the target current and the corresponding measurement voltage;

[0072] Step S1042: According to the target current and measured voltage relationship curve, the target current is extrapolated to zero to obtain the on-state voltage.

[0073] Step S105: evaluating the quality of the sidewall of the boss on the semiconductor substrate according to the on-voltage.

[0074] The present application does not limit the method for determining the damage condition of the side wall area, which can be set by the user.

[0075] As an implementation method, evaluating the quality of the sidewall of the boss on the semiconductor substrate according to the on-voltage includes:

[0076] Determining the conduction voltage range in which the conduction voltage is located according to the relationship between the preset conduction voltage range and the damage level;

[0077] The quality grade of the boss sidewall is determined according to the conduction voltage range.

[0078] For example, when the on-voltage is less than or equal to V'1, the boss sidewall surface quality grade is excellent; when the on-voltage is greater than V'1 and less than or equal to V'2, the boss sidewall surface quality grade is medium; when the on-voltage is greater than V'2, the boss sidewall surface quality grade is poor.

[0079] Of course, more types of quality levels can be set, depending on the specific situation.

[0080] The detection method in this embodiment can detect the damage of the side wall surface area during the dry etching stage, and can also detect the recovery of the side wall surface area after any recovery treatment means (such as chemical cleaning and / or heat treatment) is used after the damage, providing important information for the semiconductor manufacturing process.

[0081] The detection method in this embodiment prepares multiple components to be detected, and the thickness of the Schottky metal layer at the side wall of the boss in each component to be detected is equal, and the length is not equal. Then, a measurement voltage is applied to the Schottky contact area of ​​the side wall of the boss, so as to collect the measurement current flowing through the side wall of the boss, that is, one length corresponds to one measurement current. Under one measurement voltage, the target current of the boss flowing through the side wall when the length is zero is obtained through multiple groups of lengths and measurement currents, that is, one measurement voltage corresponds to one target current. Then, the on-voltage is obtained based on the measurement voltage and the target current. Since the target current is the current flowing through the side wall of the boss when the length of the Schottky metal layer of the side wall of the boss is zero, the on-voltage represents the Schottky barrier height of the side wall area of ​​the boss, and then the surface quality of the side wall area is detected based on the on-voltage.

[0082] The method for detecting the quality of semiconductor sidewalls based on Schottky contact in the present application is described below using a specific case.

[0083] Step 1: Prepare two components to be tested based on Schottky contact. The top view of the two components to be tested is as follows: Figure 4 and Figure 5 As shown;

[0084] Step 2: Figure 4 and Figure 5 The component to be tested shown applies a measuring voltage and collects a measuring current; Figure 4 In the component to be tested, the curve of the measured current changing with the measured voltage on the Schottky contact with a width W and a length L1 is shown in FIG. Figure 7 As shown; Figure 5 In the component to be tested, the curve of the measured current as the measured voltage changes on the Schottky contact with a width of W and a length of L2 is shown in FIG. Figure 8 As shown; for Figure 4 and Figure 5 The curve of the measured current changing with the applied measuring voltage on the Schottky contact with width W and length L1 and L2 of the component to be tested is shown in FIG. Fig. 9 As shown, in Fig. 9 In the example, a measurement voltage Vn is applied through the Schottky contact, and the measurement current is I1(n) for a graph with a width of W and a length of L1, and the measurement current is I2(n) for a graph with a width of W and a length of L2;

[0085] Step 3: Draw a curve of the relationship between the length of the Schottky metal layer on the side wall of the boss and the measured current under a measurement voltage. For example, when the measurement voltage is Vn, the curve of the relationship between the measurement current and the length of the Schottky metal layer on the side wall of the boss is as follows: Fig.10As shown, the two points in the figure are connected and extended to obtain the current when the length is 0, which is the target current I0(n); for other measurement voltages, the process is repeated to obtain multiple target currents;

[0086] Step 4: Draw the relationship curve between the target current and the measured voltage to obtain the current-voltage characteristics of the Schottky contact point in the sidewall area of ​​the boss only, such as Fig.11 As shown, by extrapolating I0(n) to zero, the on-voltage Vf representing the Schottky barrier height of the sidewall region can be obtained;

[0087] Step 5: Evaluate the damage of the sidewall region based on the obtained on-voltage.

[0088] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0089] The above is a detailed introduction to the method for detecting the quality of semiconductor sidewalls based on Schottky contact provided by the present application. This article uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A method for detecting semiconductor sidewall quality based on Schottky contact, characterized in that: include: Prepare at least two components to be detected based on Schottky contact; the components to be detected include a semiconductor substrate with a boss and a Schottky metal layer, and in each of the components to be detected, the Schottky metal layer located on the side wall of the boss has an equal thickness and an unequal length; Collecting the measurement current of each of the components to be inspected under the applied measurement voltage; the measurement voltage is at least two different voltages; the measurement current is the current flowing through the Schott metal layer located on the side wall of the boss; Under the same measurement voltage, a target current is determined according to the length of the Schott metal layer located on the side wall of the boss and the corresponding measurement current; the target current is the current flowing through the side wall of the boss when the length of the Schott metal layer located on the side wall of the boss is zero; Determining a turn-on voltage according to the target current and the corresponding measured voltage; The quality of the sidewall of the boss on the semiconductor substrate is evaluated according to the on-voltage.

2. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, characterized in that: Collecting the measured current of each of the components to be detected under the applied measuring voltage comprises: Applying the measuring voltage between the Schott metal layer and the Ohmic metal layer located on the upper surface of the boss; The measurement current is acquired.

3. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, characterized in that: Determining the target current according to the length of the Schott metal layer located on the side wall of the boss and the corresponding measured current includes: Determining a relationship between a measurement current and a length according to a length of the Schott metal layer located on a side wall of the boss and the corresponding measurement current; The target current is determined according to the relationship between the measured current and the length.

4. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 3, characterized in that: The relationship between the measured current and the length is a curve of the relationship between the measured current and the length or a formula of the relationship between the measured current and the length.

5. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, characterized in that: Determining the on-voltage according to the target current and the corresponding measured voltage includes: Determine a target current and a measured voltage relationship curve according to the target current and the corresponding measured voltage; According to the target current and measured voltage relationship curve, the target current is extrapolated to zero to obtain the on-state voltage.

6. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, characterized in that: The number of the components to be detected is two.

7. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, characterized in that: The measurement voltage includes two different voltages.

8. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, characterized in that: The material of the Schottky metal layer includes gold, aluminum, tungsten, molybdenum, and copper.

9. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, characterized in that: The material of the semiconductor substrate includes indium phosphide, gallium arsenide, silicon and germanium.

10. The method for detecting semiconductor sidewall quality based on Schottky contact according to any one of claims 1 to 9, characterized in that: Evaluating the quality of the sidewall of the boss on the semiconductor substrate according to the on-voltage includes: Determining the conduction voltage range in which the conduction voltage is located according to the relationship between the preset conduction voltage range and the damage level; The quality grade of the boss sidewall is determined according to the conduction voltage range.

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