阅读说明：本技术 一种锗铅合金材料的制备方法 (Preparation method of germanium-lead alloy material ) 是由 汪巍 方青 涂芝娟 曾友宏 蔡艳 王庆 王书晓 余明斌 于 2019-04-04 设计创作，主要内容包括：本发明提供了一种锗铅合金材料的制备方法。该方法包括：在衬底上沉积基底介质层；在基底介质层中形成开孔所述衬底从所述开孔露出的部分被作为生长种子窗口；在所述基底介质层表面以及从所述开孔露出的衬底表面沉积包含锗(Ge)元素和铅(Pb)元素的材料层；在所述材料层表面沉积阻挡介质层；以及对所述衬底进行退火,在所述材料层中形成所述四族半导体锗铅合金材料。根据本申请,能够在衬底表面形成质量较高的GePb合金,并且,该方法与CMOS工艺的兼容性较好,有利于GePb合金在硅基器件中的应用。(The invention provides a preparation method of a germanium-lead alloy material. The method comprises the following steps: depositing a base dielectric layer on a substrate; forming an opening in the base dielectric layer, wherein the part of the substrate exposed from the opening is used as a growth seed window; depositing a material layer containing germanium (Ge) and lead (Pb) on the surface of the base dielectric layer and the surface of the substrate exposed from the opening; depositing a barrier dielectric layer on the surface of the material layer; and annealing the substrate to form the group IV semiconductor germanium-lead alloy material in the material layer. According to the method, the GePb alloy with high quality can be formed on the surface of the substrate, and the method has good compatibility with a CMOS (complementary metal oxide semiconductor) process and is beneficial to application of the GePb alloy in silicon-based devices.)

1. The preparation method of the germanium-lead alloy material is characterized by comprising the following steps of:

depositing a base dielectric layer on a substrate;

forming an opening in the base dielectric layer, wherein the part of the substrate exposed from the opening is used as a growth seed window;

depositing a material layer containing germanium (Ge) and lead (Pb) on the surface of the base dielectric layer and the surface of the substrate exposed from the opening;

depositing a barrier dielectric layer on the surface of the material layer; and

and annealing the substrate to form the group IV semiconductor germanium-lead alloy material in the material layer.

2. The method of claim 1, wherein,

the substrate includes a single crystal silicon (Si) substrate or a single crystal (Ge) substrate.

3. The method of claim 1, wherein,

the substrate dielectric layer comprises silicon nitride (SiN) and/or silicon oxide (SiO)₂)，

The thickness of the substrate dielectric layer is 20-200 nm.

4. The method of claim 1, wherein the method further comprises:

and cleaning the opening to remove the oxide layer on the surface of the substrate exposed from the opening.

5. The method of claim 1, wherein,

the material layer containing a germanium (Ge) element and a lead (Pb) element includes:

a stacked material layer containing at least a first germanium (Ge) material layer, a lead (Pb) material layer, and a second germanium (Ge) material layer in a thickness direction; alternatively, the first and second electrodes may be,

a single-layer material layer containing a germanium (Ge) element and a lead (Pb) element.

6. The method of claim 1, wherein,

the material layer containing germanium (Ge) element and lead (Pb) element has a thickness of 50-300 nm.

7. The method of claim 1, wherein the method further comprises:

and etching the material layer containing germanium (Ge) and lead (Pb) elements to form the material layer into a strip shape on a plane parallel to the surface of the substrate.

8. The method of claim 1, wherein,

the barrier dielectric layer comprises silicon nitride (SiN) and/or silicon oxide (SiO)₂) The thickness of the blocking dielectric layer is 200-1000 nm.

9. The method of claim 1, wherein,

the annealing may comprise high temperature annealing or laser annealing,

wherein the temperature of the high-temperature annealing is 800-1200 ℃, the time is 1 second-10 minutes,

the laser energy density of the laser annealing is 200-800mJ/cm²The pulse number is 1-100.

Technical Field

The invention belongs to the field of semiconductor materials, and particularly relates to a preparation method of a germanium-lead (GePb) alloy material.

Background

Germanium tin (GeSn) material as a novel four-group alloy material has a large absorption coefficient in near infrared photoelectricity and even short wave infrared, and is an important choice for preparing silicon-based infrared photoelectric detectors. Meanwhile, when the Sn component reaches 8%, the GeSn alloy can be converted into a direct band gap material, so that the GeSn alloy is expected to be used for preparing a silicon-based semiconductor laser. However, limited by the low solid solubility (< 1%) of Sn in Ge, the synthesis of GeSn alloys with high quality Sn components is extremely challenging.

In recent years, it has been found that the band structure can be effectively modulated by introducing another group IV material, lead (Pb), into Ge. For example, by introducing a certain proportion of Pb, the transition from an indirect bandgap material to a direct bandgap material can be achieved, which provides a new material choice for the implementation of a silicon-based light source.

Disclosure of Invention

The inventors of the present application have found that although there are some methods of forming germanium-lead (GePb) alloys, these methods have certain limitations, such as: few technologies can form GePb alloys on silicon substrates, and thus, compatibility with CMOS processes is poor; in addition, even if the GePb alloy is epitaxially formed on the silicon substrate, dislocations are easily formed in the GePb alloy and/or the silicon substrate due to lattice mismatch of the GePb alloy and silicon, and thus the quality of the GePb alloy is low and the electrical properties of the substrate may be affected; in addition, the quality of the GePb alloys formed by the prior art is not high.

The invention aims to provide a preparation method of a four-group semiconductor GePb alloy material, in the preparation method, a material layer containing Ge and Pb is formed on the surfaces of a growth seed window and a base medium layer, then annealing is carried out, so that a single-crystal GePb alloy is formed in the material layer containing Ge and Pb, and because the material layer containing Ge and Pb is only contacted with a substrate at the growth seed window, dislocation generated by lattice mismatch does not extend to the whole GePb layer, and a GePb alloy with higher quality can be formed; in addition, during the annealing process, metal Pb formed by Pb segregation can induce the synthesis of the single crystal GePb, so that the formation of the single crystal GePb alloy is promoted; in addition, the method can generate a high-quality GePb alloy material on the silicon substrate, so that the method has good compatibility with a CMOS (complementary metal oxide semiconductor) process and is beneficial to the application of the GePb alloy in silicon-based devices.

The purpose of the invention is realized by the following technical scheme:

a preparation method of a germanium-lead alloy material is based on metal induced crystallization and comprises the following steps:

1) depositing a base medium layer on the substrate, forming a hole on the base medium layer through photoetching to form a seed growing window, cleaning the substrate exposed at the seed window, and removing a surface oxide layer;

2) depositing a material layer containing germanium (Ge) element and lead (Pb) element on the substrate surface exposed at the seed window in the step 1) and the substrate on the surface of the base medium layer; in addition, the material layer can be formed into a strip-shaped structure connected with the seed window through etching;

3) depositing a barrier dielectric layer on the surface of the material layer containing germanium (Ge) element and lead (Pb) element in the step 2);

4) and carrying out high-temperature annealing or laser annealing on the substrate in the step 3), and forming a single-crystal germanium-lead alloy material in the material layer containing the germanium (Ge) element and the lead (Pb) element.

According to the present invention, in step 1), the substrate may be a single crystal substrate, for example, a silicon single crystal substrate or a germanium (Ge) single crystal substrate.

According to the invention, in step 1), the base dielectric layer can be SiN and/or SiO₂A dielectric layer, the thickness of the substrate dielectric layer is 20-200nm, such as 20nm,30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 120nm, 150nm, 180nm or 200 nm. The deposition can be a Plasma Enhanced Chemical Vapor Deposition (PECVD) method, and other methods for realizing the deposition of the substrate dielectric layer can also be adopted.

According to the invention, in the step 1), the opening is formed by opening a window for growing the seeds in any shape or structure on the base medium layer, the substrate is directly exposed out through the window, and the exposed substrate is easily oxidized to generate an oxide layer, so that the substrate can be cleaned, for example, by using hydrofluoric acid solution.

According to the invention, in step 2), the deposition may be performed by Molecular Beam Epitaxy (MBE) or by magnetron sputtering (Sputter). The deposited material layer can be a laminated material layer formed by depositing a Ge material layer, a Pb material layer and a Ge material, or a single-layer material layer formed by depositing the Ge material and the Pb material simultaneously. In the material layer, the mole ratio percentage of the simple substance Pb to the simple substance Ge is, for example, (2-20): (80-98), for example, if Ge and Pb are deposited simultaneously, the mole ratio percentage of Pb to Ge deposited is (2-20): (80-98). If Ge, Pb and Ge are deposited separately to form a stack, the Ge layer thickness > > the Pb layer thickness, and the molar ratio percentage of Pb elementary substance to Ge elementary substance is still guaranteed to be (2-20): (80-98).

According to the invention, in step 2), the thickness of the deposited GePb layer is 50-300nm, such as 60nm, 80nm, 90nm, 100nm, 120nm, 130nm, 150nm, 160nm, 180nm, 200nm, 220nm, 250nm, 280nm, 300 nm.

According to the invention, in the step 2), the material layer containing Ge and Pb may be etched to form a GePb layer stripe structure connected to the seed window.

According to the invention, in step 3), the blocking dielectric layer may be silicon nitride (SiN) or silicon oxide (SiO)₂) And the thickness of the blocking dielectric layer is 200-1000nm, such as 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm and 1000 nm). The deposition may be by plasmaA daughter-enhanced chemical vapor deposition (PECVD) method, or other methods that can achieve the deposition of the barrier dielectric layer, may also be used.

According to the invention, in the step 4), the temperature of the high-temperature annealing is 800-; laser energy density for laser annealing 200-800mJ/cm²The pulse frequency is 1-100; and crystallizing GePb at the seed window by high-temperature annealing or laser annealing, and then transversely growing along the GePb strip structure. Because of the low solid solubility of Pb in Ge, Pb metal is formed at the crystallization site upon annealing, which is capable of inducing the synthesis of single crystal GePb. The high-temperature annealing can be rapid high-temperature annealing, so that a metastable GePb alloy exceeding the solid solubility concentration can be formed in the material layer containing germanium and lead by crystallization through the rapid high-temperature annealing or laser annealing method, namely the GePb crystallization can be rapidly realized through the high-temperature annealing or laser annealing method. In addition, during the annealing process, the material layer containing germanium and lead is in direct contact with the substrate through the growth seed window, so that the contact area of the material layer and the substrate is small, the dislocation generated by lattice mismatch is less, and the dislocation cannot extend to the whole material layer containing germanium and lead, so that the quality of the GePb alloy of the single crystal is high.

The invention has the beneficial effects that:

the invention provides a preparation method of a GePb alloy material. The preparation method has the following advantages:

the method comprises the steps of forming a material layer containing Ge and Pb on the surface of a growth seed window and the surface of a base medium layer, then annealing, and forming a single-crystal GePb alloy in the material layer containing Ge and Pb.

Drawings

FIG. 1: the invention relates to a flow chart of a preparation method of a four-group GePb alloy material.

FIG. 2: the cross-sectional structure of the preparation method of the four-group GePb alloy material is shown schematically.

Detailed Description

The preparation method of the present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.

The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.