A method for detecting semiconductor sidewall quality based on Schottky contact

Abstract

This application relates to the semiconductor field and discloses a method for detecting semiconductor sidewall quality based on Schottky contacts. The method includes preparing at least two components to be detected based on Schottky contacts; the components to be detected include a semiconductor substrate having a boss and a Schottky metal layer; in each component to be detected, the Schottky metal layer located on the boss sidewall has equal thickness but unequal length; collecting a measurement current from each component to be detected under an applied 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 boss sidewall; under the same measurement voltage, a target current is determined based on the length of the Schottky metal layer located on the boss sidewall and the corresponding measurement current; the target current is the current when the length of the Schottky metal layer located on the boss sidewall is zero; determining a turn-on voltage based on the target current and the corresponding measurement voltage; and evaluating the quality of the boss sidewall based on the turn-on voltage. This application can achieve sidewall quality detection.

Description

Technical Field

[0001] The present application relates to the field of semiconductors, 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 semiconductor surfaces by processes such as dry etching. Currently, when detecting damage to semiconductor surfaces 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 having 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 electron / ion bombardment effects, deposition of reaction products, and / or atomic mismatch in the surface area of ​​the semiconductor substrate, damaged layers are generated in the front surface area (Y) and sidewall area (X) of the semiconductor substrate surface. The front surface area and the sidewall area correspond to the Schottky metal layer.

[0003] By continuously applying voltage between the Schottky metal layer and the ohmic contact layer and sampling the corresponding current, a voltage-current curve is generated. The on-state voltage, representing the Schottky barrier height, is then determined based on the voltage-current curve. The damage to the front surface region of the semiconductor substrate can then be assessed based on the magnitude of the on-state voltage. Assessment of the front surface region is possible because the contact area (L×W) between the Schottky metal layer and the front surface region is much larger than the contact area (D×W) with the sidewall region, where L>>D, where L is the length of the Schottky metal layer in the front surface region, W is the width of the Schottky metal layer, and D is the height of the protrusion. However, damage detection in the sidewall region is not possible.

[0004] Therefore, how to solve the above technical problems should be the focus of those skilled in the art. Summary of the Invention

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

[0006] To solve the above technical problems, the present application provides a method for detecting semiconductor sidewall quality based on Schottky contact, comprising:

[0007] Prepare at least two components to be tested based on Schottky contacts; the components to be tested include a semiconductor substrate having a boss and a Schottky metal layer, and in each of the components to be tested, the Schottky metal layer located on the sidewall of the boss has the same thickness and different lengths;

[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 Schottky metal layer located on the side wall of the boss;

[0009] Under the same measurement voltage, a target current is determined based on the length of the Schottky 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 Schottky 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 mesa on the semiconductor substrate is evaluated according to the turn-on voltage.

[0012] Optionally, collecting the measured current of each component to be inspected under the applied measurement voltage includes:

[0013] applying the measurement voltage between the Schottky 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 Schottky metal layer located on the sidewall 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 Schottky metal layer located on a sidewall 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 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.

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

[0020] Determining a target current and measurement voltage relationship curve according to the target current and the corresponding measurement voltage;

[0021] According to the relationship curve between the target current and the measured voltage, 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 measured 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 within which the conduction voltage falls according to a relationship between a preset conduction voltage range and a 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 contacts, comprising: preparing at least two components to be detected based on Schottky contacts; the components to be detected include a semiconductor substrate having a boss and a Schottky metal layer, and in each of the components to be detected, the Schottky metal layer located on the sidewall of the boss has the same thickness and different lengths; collecting the measured current of each component to be detected under the application of a measurement voltage; the measurement voltage is at least two different voltages; the measured current is the current flowing through the Schottky metal layer located on the sidewall of the boss; under the same measurement voltage, determining a target current according to the length of the Schottky metal layer located on the sidewall of the boss and the corresponding measurement current; the target current is the current flowing through the sidewall of the boss when the length of the Schottky metal layer located on the sidewall 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 sidewall 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 boss side wall to collect the measurement current flowing through the boss side wall, 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 of the boss side wall area, 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 following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0032] Figure 1 Schematic diagram of the structure 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 tested and collecting a measurement current in this embodiment;

[0037] Figure 7 for Figure 4 A graph showing the change in measured current of a component to be tested as the measured voltage changes;

[0038] Figure 8 for Figure 5 A graph showing the change in measured current of a component to be tested as the measured voltage changes;

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

[0040] Figure 10 is a graph showing the relationship between the measured current and the length of the Schottky metal layer on the sidewall of the boss in this embodiment;

[0041] Figure 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 embodiments. Obviously, the embodiments described are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative efforts 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. However, the present invention may also be implemented in other ways different from those described herein. 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 condition of the front surface region of the semiconductor substrate surface based on Schottky contact can be detected, while the damage condition of the sidewall region cannot be detected.

[0045] In view of this, this 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 tested based on Schottky contact; the components to be tested include a semiconductor substrate with a boss and a Schottky metal layer, and in each of the components to be tested, the Schottky metal layer located on the sidewall 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 can be an N-type substrate or a P-type substrate, both of which are within the protection scope of this 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 tested can be directly used as it is already prepared, or can be prepared by itself. The process of preparing each component to be tested 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 this application and is determined according to the circumstances, for example, the number of components to be detected may be two, three, or four.

[0054] For different components to be inspected, the thickness of the Schottky metal layer on the side wall of the boss is equal, but the length is different. Taking the number of components to be inspected as two 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 Schottky metal layer on the side wall of the boss is H, and the length is L1; Figure 5 The thickness of the Schottky 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 Schottky metal layer located on the side wall of the boss.

[0056] As an implementation method, collecting the measured current of each component to be detected under the applied measurement voltage includes:

[0057] applying the measurement voltage between the Schottky 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 the measurement voltage and collecting the measurement current on the component to be detected in this embodiment is as follows: Figure 6 shown.

[0060] It should be noted that the present application does not limit the number of measurement voltages, which may be determined based on the circumstances. For example, the measurement voltages may include two, three, or four different voltages.

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

[0062] Step S103: Under the same measurement voltage, determine the target current according to the length of the Schottky 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 Schottky metal layer located on the side wall of the boss is zero.

[0063] As an implementation method, determining the target current according to the length of the Schottky metal layer located on the sidewall 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 Schottky metal layer located on a sidewall 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 based on (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 based on (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 based on (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] Based on the relationship between each measured current and length, a target current I0 can be determined. Therefore, each measured voltage corresponds to a 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). Similarly, 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: extrapolating the target current to zero according to the target current and measured voltage relationship curve 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] This application does not limit the method for determining the damage condition of the sidewall area, and it can be set by yourself.

[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 within which the conduction voltage falls according to a relationship between a preset conduction voltage range and a damage level;

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

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

[0079] Of course, more 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 tested, and the thickness of the Schottky metal layer at the side wall of the boss in each component to be tested is equal, and the length is unequal. Then, a measurement voltage is applied to the Schottky contact area of ​​the boss side wall to collect the measurement current flowing through the boss side wall, 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 by multiple sets 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 of the boss side wall area, and then the surface quality of the side wall area is detected based on the on-voltage.

[0082] The method for detecting semiconductor sidewall quality based on Schottky contact in this 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 A measurement voltage is applied to the component to be tested, and a measurement current is collected; Figure 4 In the component to be tested, the curve of the measured current versus the measured voltage on the Schottky contact with a width of W and a length of 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 as the applied measurement voltage changes on the Schottky contact with width W and length L1 and L2 of the component to be tested is shown in FIG. Figure 9 As shown, in Figure 9 In the example, a measurement voltage Vn is applied through the Schottky contact. For a graph with width W and length L1, the measured current is I1(n). For a graph with width W and length L2, the measured current is I2(n).

[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: Figure 10As shown, connect the two points in the figure and extend them to obtain the current when the length is 0, which is the target current I0(n); repeat this process for other measurement voltages 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, such as Figure 11 As shown, by extrapolating I0(n) to zero, the turn-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-state 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 semiconductor sidewall quality based on Schottky contact provided by this application. This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the scope of protection of the claims of this 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 tested based on Schottky contacts; the components to be tested include a semiconductor substrate having a boss and a Schottky metal layer, and in each of the components to be tested, the Schottky metal layer located on the sidewall of the boss has the same thickness and different lengths; 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 Schottky metal layer located on the side wall of the boss; Under the same measurement voltage, a target current is determined based on the length of the Schottky 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 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 measured voltage; evaluating the quality of the sidewall of the boss on the semiconductor substrate according to the on-voltage; Collecting the measured current of each of the components to be detected under the applied measurement voltage includes: applying the measurement voltage between the Schottky metal layer and the ohmic metal layer located on the upper surface of the boss; collecting the measured current; Determining the target current according to the length of the Schottky metal layer located on the sidewall of the boss and the corresponding measured current includes: Determining a relationship between a measured current and a length according to a length of the Schottky metal layer located on a sidewall of the boss and the corresponding measured current; The target current is determined according to the relationship between the measured current and the length.

2. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, wherein: 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.

3. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, wherein: Determining the turn-on voltage according to the target current and the corresponding measured voltage includes: Determining a target current and measurement voltage relationship curve according to the target current and the corresponding measurement voltage; According to the relationship curve between the target current and the measured voltage, the target current is extrapolated to zero to obtain the on-state voltage.

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

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

6. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, wherein: The material of the Schottky metal layer includes gold, aluminum, tungsten, molybdenum or copper.

7. The method for detecting semiconductor sidewall quality based on Schottky contact according to claim 1, wherein: The material of the semiconductor substrate includes indium phosphide, gallium arsenide, silicon or germanium.

8. The method for detecting semiconductor sidewall quality based on Schottky contact according to any one of claims 1 to 7, 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 within which the conduction voltage falls according to a relationship between a preset conduction voltage range and a damage level; The quality grade of the boss sidewall is determined according to the conduction voltage range.

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