An epitaxial method for improving adhesion defects on a polycrystalline gate overlay

Abstract

The present invention provides an epitaxial method for improving the adhesion defects on a polycrystalline gate coverage layer, comprising providing a substrate and polycrystalline gates spaced apart from each other on the substrate; a source / drain epitaxial region is formed between the polycrystalline gates; a groove is formed in the source / drain epitaxial region; a seed layer is epitaxially formed in the groove by adding an HCl atmosphere; a bulk layer is epitaxially formed on the seed layer by adding an HCl atmosphere; a cap layer is epitaxially formed on the bulk layer; HCl is introduced as an etching gas, and GeH4 atmosphere is in-situ introduced to catalyze and enhance the etching, so that the cap layer is etched back. The present invention provides a germanium-silicon in-situ catalytic epitaxial method for improving the adhesion defects on a polycrystalline gate coverage layer, comprising a seed layer, as well as a bulk layer and a cap layer. The etching selectivity for the thin film in the source / drain region and the defects in the polycrystalline gate coverage region is improved, and the defects at the polycrystalline gate coverage layer are quickly eliminated when the cap layer is etched back, completing the entire epitaxial process, thereby meeting the requirements of maintaining the yield and high production capacity output of the device simultaneously.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to an epitaxial method for improving the attachment defects on a polycrystalline gate covering layer. Background Art

[0002] Stress channel transistors have been widely studied in the integrated circuit industry. In PMOS, the embedded SiGe source / drain technology can further improve the carrier mobility of the channel, thereby improving the performance of the device. Furthermore, the size of the transistor can be continuously reduced to achieve a higher degree of integration. In PMOS, the embedded SiGe source / drain epitaxial method is adopted: first, a seed layer with low Ge and B is epitaxially grown to reduce the lattice mismatch between the epitaxial layer and the substrate. Then, a bulk layer doped with a higher concentration of Ge and B is epitaxially grown. The distribution of the channel stress field and the source / drain end current field can be simultaneously regulated by the B and Ge concentrations in the bulk layer. Finally, Si:B is epitaxially grown as a cap layer. During the entire epitaxial process, an HCl atmosphere needs to be added synchronously to inhibit the attachment growth in non-required regions such as the polycrystalline gate covering layer, so as to selectively epitaxially grow the source / drain region at a fixed point. With the continuous increase of the integrated pattern density, the nucleation centers on the polycrystalline gate covering layer increase continuously, resulting in the formation of more attachment defect particles and reducing the yield of the device. Although continuously increasing the HCl atmosphere can inhibit the defect growth at the polycrystalline gate, it greatly reduces the growth rate of the source / drain region, making the epitaxial process become the production capacity bottleneck of the production line. Summary of the Invention

[0003] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide an epitaxial method for improving the attachment defects on a polycrystalline gate covering layer, which is used to solve the problem that the growth rate of the source / drain region is reduced by introducing HCl during the epitaxial cap layer in the prior art.

[0004] To achieve the above purpose and other related purposes, the present invention provides an epitaxial method for improving the attachment defects on a polycrystalline gate covering layer, which at least includes:

[0005] Step 1: Provide a substrate with polycrystalline gates spaced apart from each other thereon; the source / drain epitaxial regions are located between the polycrystalline gates; grooves are formed in the source / drain epitaxial regions;

[0006] Step 2: Epitaxially grow a seed layer in the grooves by adding an HCl atmosphere;

[0007] Step 3: Epitaxially grow a bulk layer on the seed layer by adding an HCl atmosphere;

[0008] Step 4: Epitaxially grow a cap layer on the bulk layer;

[0009] Step 5: Introduce HCl as the etching gas, and simultaneously introduce a GeH4 atmosphere in-situ to catalytically enhance the etching, causing the capping layer to be etched back.

[0010] Preferably, in Step 2, the seed layer is formed by epitaxially growing Ge and B.

[0011] Preferably, in Step 3, the body layer is formed by epitaxial doping of Ge and B.

[0012] Preferably, the doping concentrations of Ge and B in the body layer formed in Step 3 are greater than those of Ge and B in the seed layer in Step 2.

[0013] Preferably, Ge and B in the body layer formed in Step 3 are used to simultaneously regulate the distribution of the channel stress field and the source-drain current field.

[0014] Preferably, the material of the capping layer formed in Step 4 is Si.

[0015] Preferably, the introduction of the HCl atmosphere is cancelled during the epitaxial growth of the capping layer in Step 4.

[0016] Preferably, in Step 5, HCl is introduced as the etching gas, and simultaneously a GeH4 atmosphere is introduced in-situ to catalytically enhance the etching. The diffusion of Ge into the interior is easier on the defective surface of the polycrystalline gate than on the capping layer surface, thereby accelerating the etching rate.

[0017] Preferably, in Step 5, HCl is introduced as the etching gas, and simultaneously a GeH4 atmosphere is introduced in-situ to catalytically enhance the etching, improving the etching selectivity for defects in the source-drain region and the polycrystalline gate coverage region, and rapidly eliminating the defects at the polycrystalline gate coverage layer during the back-etching of the capping layer.

[0018] As described above, the epitaxial method for improving the attachment defects on the polycrystalline gate coverage layer of the present invention has the following beneficial effects: The present invention provides a germanium-silicon in-situ catalytic epitaxial method for improving the attachment defects on the polycrystalline gate coverage layer, including a seed layer, a body layer, and a capping layer. It improves the etching selectivity for defects in the source-drain region thin film and the polycrystalline gate coverage region, rapidly eliminates the defects at the polycrystalline gate coverage layer during the back-etching of the capping layer, and completes the entire epitaxial process, thereby meeting the requirements of maintaining the yield and high production capacity of the device simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It shows a schematic structural diagram of the source-drain epitaxial region provided between polycrystalline gates in the present invention;

[0020] Figure 2 It shows a schematic structural diagram after the formation of the seed layer in the present invention;

[0021] Figure 3 It shows a schematic structural diagram after the formation of the body layer in the present invention;

[0022] Figure 4 It shows a schematic structural diagram after forming a capping layer in the present invention;

[0023] Figure 5 It shows a schematic structural diagram formed after etching back the capping layer in the present invention;

[0024] Figure 6 It shows a flowchart of an epitaxial method for improving adhesion defects on a polycrystalline gate overlay in the present invention. Detailed implementation manners

[0025] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0026] Please refer to Figures 1 to 6 . It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components during actual implementation. The type, quantity, and ratio of each component during actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0027] The present invention provides an epitaxial method for improving adhesion defects on a polycrystalline gate overlay, as Figure 6 shown, Figure 6 It shows a flowchart of an epitaxial method for improving adhesion defects on a polycrystalline gate overlay in the present invention, including at least the following steps:

[0028] Step 1: Provide a substrate, and polycrystalline gates spaced apart from each other on the substrate; the source-drain epitaxial regions are between the polycrystalline gates; grooves are formed in the source-drain epitaxial regions; as Figure 1 shown, Figure 1 It shows a schematic structural diagram of the source-drain epitaxial regions provided between the polycrystalline gates in the present invention. In this step 1, a substrate 01 is provided, and polycrystalline gates 02 spaced apart from each other are on the substrate 01. Among them, the source-drain epitaxial regions are between the polycrystalline gates 02; grooves 03 are formed in the source-drain epitaxial regions.

[0029] Step 2: Epitaxially form a seed layer in the grooves by adding an HCl atmosphere; as Figure 2 shown, Figure 2 It shows a schematic structural diagram after forming the seed layer in the present invention. In this step 2, a seed layer 04 is epitaxially formed in the grooves 03 by adding an HCl atmosphere.

[0030] Furthermore, in the present invention, in step two of this embodiment, the seed layer is formed by epitaxially growing Ge and B.

[0031] Step three: An epitaxial body layer is formed on the seed layer by adding an HCl atmosphere; as Figure 3 shown, Figure 3 It shows a schematic structural diagram after the formation of the body layer in the present invention. In this step three, an epitaxial body layer 05 is formed on the seed layer 04 by adding an HCl atmosphere.

[0032] Furthermore, in the present invention, in step three of this embodiment, the body layer is formed by epitaxially growing Ge and B with doping.

[0033] Furthermore, in the present invention, in this embodiment, the doping concentrations of Ge and B in the body layer formed in step three are greater than those of Ge and B in the seed layer in step two.

[0034] Furthermore, in the present invention, in this embodiment, Ge and B in the body layer formed in step three are used to simultaneously regulate the distribution of the channel stress field and the source-drain terminal current field.

[0035] Step four: An epitaxial cap layer is formed on the body layer; as Figure 4 shown, Figure 4 It shows a schematic structural diagram after the formation of the cap layer in the present invention. In this step four, an epitaxial cap layer 06 is formed on the body layer 05.

[0036] Furthermore, in the present invention, in this embodiment, the material of the cap layer formed in step four is Si.

[0037] Furthermore, in the present invention, in this embodiment, the introduction of the HCl atmosphere is cancelled during the process of epitaxially growing the cap layer in step four.

[0038] Step five: HCl is introduced as an etching gas, and at the same time, a GeH4 atmosphere is introduced in-situ to catalytically enhance the etching, so that the cap layer is etched back. As Figure 5 shown, Figure 5 It shows a schematic structural diagram formed after the etching back of the cap layer in the present invention.

[0039] Furthermore, in the present invention, in this embodiment, HCl is introduced as an etching gas, and at the same time, a GeH4 atmosphere is introduced in-situ to catalytically enhance the etching. The etching rate is accelerated by the fact that Ge diffuses more easily into the interior on the defective surface of the polycrystalline gate than on the surface of the cap layer.

[0040] Furthermore, in the present invention, in this embodiment, HCl is introduced as an etching gas, and at the same time, a GeH4 atmosphere is introduced in-situ to catalytically enhance the etching, which improves the etching selectivity for the defects in the source-drain region and the polycrystalline gate coverage region, and rapidly eliminates the defects at the polycrystalline gate coverage layer when etching back the cap layer.

[0041] The present invention provides a germanium-silicon in-situ catalytic epitaxial method for improving adhesion defects on a polycrystalline gate coverage layer, which includes a seed layer, a bulk layer, and a cap layer. In the epitaxial method, for the growth of the cap layer, the HCL atmosphere is cancelled, so that the growth rate of the cap layer Si is greatly increased. At the same time, the adhesion defects at the polycrystalline gate coverage layer grow freely without the etching inhibition of HCL. After the growth of the cap layer Si is completed, HCL is introduced as an etching gas while GeH4 atmosphere is introduced in-situ to catalyze and enhance the etching ability. Since Ge diffuses more easily into the interior on the defect surface than on the cap layer Si surface, the etching rate is accelerated, thereby improving the etching selectivity for the source-drain region thin film and the defects in the polycrystalline gate coverage region. When the cap layer Si is etched back, the defects at the polycrystalline gate coverage layer are quickly eliminated, and the entire epitaxial process is completed, so as to meet the requirements of maintaining the yield and high production capacity of the device at the same time.

[0042] In summary, the present invention provides a germanium-silicon in-situ catalytic epitaxial method for improving adhesion defects on a polycrystalline gate coverage layer, which includes a seed layer, a bulk layer, and a cap layer. The etching selectivity for the source-drain region thin film and the defects in the polycrystalline gate coverage region is improved. When the cap layer is etched back, the defects at the polycrystalline gate coverage layer are quickly eliminated, and the entire epitaxial process is completed, so as to meet the requirements of maintaining the yield and high production capacity of the device at the same time. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0043] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. An epitaxial method for improving the adhesion defects on a polycrystalline gate overlay, characterized in that, it at least includes: Step 1: Provide a substrate with polycrystalline gates spaced apart from each other thereon; a source-drain epitaxial region is formed between the polycrystalline gates; a groove is formed in the source-drain epitaxial region; Step 2: Epitaxially form a seed layer in the groove by adding an HCl atmosphere; Step 3: Epitaxially form a body layer on the seed layer by adding an HCl atmosphere; Step 4: Epitaxially form a cap layer on the body layer; the introduction of the HCl atmosphere is cancelled during the process of epitaxially forming the cap layer; the cap layer material is Si; Step 5: Introduce HCl as an etching gas, and simultaneously introduce a GeH4 atmosphere in-situ to catalyze and enhance etching, so that the Si cap layer is etched back. Utilize the fact that Ge diffuses more easily into the interior on the adhesion defect surface of the polycrystalline gate than on the Si cap layer surface to accelerate the etching rate; at the same time, introduce a GeH4 atmosphere in-situ to catalyze and enhance etching to improve the etching selectivity for the defects in the source-drain region and the polycrystalline gate coverage region, and quickly eliminate the defects at the polycrystalline gate coverage layer when etching back the cap layer.

2. The epitaxial method for improving the adhesion defects on a polycrystalline gate overlay according to claim 1, characterized in that: The seed layer is formed by epitaxially growing Ge and B in Step 2.

3. The epitaxial method for improving the adhesion defects on a polycrystalline gate overlay according to claim 2, characterized in that: The body layer is formed by epitaxially doping Ge and B in Step 3.

4. The epitaxial method for improving the adhesion defects on a polycrystalline gate overlay according to claim 3, characterized in that: The doping concentrations of Ge and B in the body layer formed in Step 3 are greater than the doping concentrations of Ge and B in the seed layer in Step 2.

5. The epitaxial method for improving the adhesion defects on a polycrystalline gate overlay according to claim 1, characterized in that: Ge and B in the body layer formed in Step 3 are used to simultaneously regulate the distribution of the channel stress field and the source-drain end current field.

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