CN100533665C - Preparation of InN/germanium or InN/silicon thin film with InN material as substrate or cushion breaker and preparation method - Google Patents

Abstract

InN material is used as substrate or buffer layer to prepare InN/germanium or InN/silicon film, InN material is used as substrate or buffer layer, and InN/germanium or InN/silicon film is prepared on it, and the thickness of InN material buffer layer is more than 100 nanometers , preparing a single layer or n layers of germanium or silicon thin film on it, and the thickness of each layer of germanium or silicon thin film is more than 50 nanometers. The invention grows InN/germanium or InN/silicon film by using MOCVD, CVD, HVPE or MBE growth technology within the growth temperature range of 200-1150°C. The heterostructure is obtained by taking advantage of the insignificant lattice mismatch ratio (9%) and the slight difference in bandgap (40meV) between Ge(111) and InN. The advantages of such heterostructures for producing heterojunction bipolar transistors (HBTs) as well as infrared light detectors are numerous.

Description

InN material used as substrate or buffer layer to prepare InN/germanium or InN/silicon film and preparation method

technical field

The invention relates to a method for growing other semiconductor materials or structures using InN material as a buffer layer or substrate material. In particular, a single-layer semiconductor material or a multi-layer semiconductor structure material is grown on a single crystal or polycrystalline InN semiconductor material by using CVD, MOCVD or MBE growth methods.

Background technique

With the development of the semiconductor industry to today's third-generation semiconductor materials, group III nitrides composed of GaN, InN, AlN and their ternary alloys In _x Ga _1-x N, Al _x Ga _1-x N have many unique Its characteristics and wide application prospects have become a hot spot in the research and development of semiconductor optoelectronics in recent years. In 2002, W.Walukiewicz and J.Wu of the Lawrence Berkeley National Laboratory in the United States found that the band gap of InN was 0.7eV ([1] J.Wu, W.Walukiewicz, KMYu, JWAger III, EEHaller, H.Lu, WJSchaff , Y.Saito, and Y.Nanishi, Appl.Phys.Lett.80, 3967 (2002)), rather than the previously reported 2eV ([2] TLTansley and CPFoley, J.Appl.Phys.59, 3241 (1986) ). This makes the band gap of III-nitride alloys continuously adjustable from 6.2eV of AlN to 0.7eV of InN, and the wavelength of the corresponding absorption spectrum can extend from the ultraviolet part to the near-infrared part, which almost completely covers the entire Solar Spectrum ([3] J.Wu, W.Walukiewicz, KMYu, W.Shan, JWAger III, EEHaller, Hai Lu, William J.Schaff, WKMetzger and Sarah Kurtz, J.Appl.Phys.94, 6477(2003) ), the spectral coverage of the InGaN ternary alloy and the corresponding situation of the AM1.5 solar spectrum are given in the literature; and InGaN is compared with traditional materials GaInP, GaAs and Ge. It provides an almost perfect corresponding matching energy gap to the solar spectrum. This opens up great possibilities for designing new types of high-efficiency solar cells. If this material is used to manufacture solar cells, especially in the manufacture of tandem solar cells, it is only necessary to change the composition of different metals in the ternary alloy to easily adjust the absorption window without growing another Material. This will allow greater freedom in the design and growth of tandem cells, which will facilitate optimal window combinations. If it is considered that the number of InGaN cell junctions is ideally made enough, its theoretical maximum conversion efficiency can reach 85% ([4]Antonio Marti, Gerardo L.Arafijo, SolarEnergy Materials and Solar Cells, 43, 203(1996 )).

CVD, MOCVD or MBE are relatively mature growth methods for semiconductor materials, such as CN1389904, the method for growing high-quality GaN thin films by lateral epitaxy, using MOCVD, MBE or other methods to grow GaN seed layers; depositing on GaN seed layers SiO2, Si3N4, W and other films. CN1945863 Composite buffer layer grown on sapphire substrate and its preparation method adopts MBE growth mode, and sequentially arranges AlN layer, GaN layer, InN:Mn layer and InN transition layer.

Among group III nitride semiconductor materials, indium nitride (InN) has the smallest electron effective mass, the highest electron mobility, the largest peak and saturation electron drift rates, and the smallest forbidden band width. Therefore, InN has great application value in high-frequency and high-speed electronic devices. The bandgap width of InN reported earlier is about 1.89eV, but the research results since 2002 show that the bandgap width of InN is far from 1.89eV, and may be around 0.7eV. InN has become a new hotspot in the research of nitride semiconductors. Since the band gap of InN is about 0.7eV, the nitride alloy material can cover the deep ultraviolet to near infrared band (200-1600nm), and will have great application value in optoelectronic devices. First of all, the 1.3μm and 1.55μm optical fiber communication windows are within this wavelength range, which makes it possible for InN-based semiconductor materials to have important applications in optical fiber communication devices, such as high-speed LD and photodetection devices.

Si and Ge are currently the most widely used semiconductor materials. With the development of science and technology, the existing materials can no longer meet the needs of industry, so people turn their attention to heterostructure semiconductor materials. The modest lattice mismatch ratio (9%) between Ge(111) and InN and the small difference in bandgap (40meV) make it easy to think of a heterostructure between these two materials. The exploration of this heterostructure is likely to contribute to the development of heterojunction bipolar transistors (HBTs) and infrared photodetectors.

InN is a new type of semiconductor material with good prospects, but because its research has just started, many characteristics of this material are still under study, especially the use of it as a buffer layer or substrate material has not been reported in the literature. CVD (chemical vapor phase epitaxy), MOCVD (metal organic chemical vapor phase epitaxy) and MBE (molecular beam epitaxy) technology growth methods are commonly used material growth methods, but the substrate InN material is selected as a buffer layer or substrate material to grow other semiconductor materials Or semiconductor structural materials are worthy of our research, including the technical conditions of growth, the design of the buffer layer, etc. are all problems that need to be solved in production. The combination of new semiconductor InN materials and traditional semiconductor Si and Ge materials may produce new semiconductor structures and new semiconductor phenomena.

The invention selects the novel semiconductor material InN as the buffer layer or the substrate material, and epitaxially grows the semiconductor Ge film material by using the CVD method. The properties of Ge epitaxial films grown on InN materials by epitaxial growth by CVD were studied. The Ge thin film material grown on the InN single crystal material was preliminarily obtained. And apply for invention protection method of using InN material as buffer layer or substrate material to grow other semiconductor materials or structures. Especially use single crystal or polycrystalline InN semiconductor material as buffer layer or substrate material, and use CVD, MOCVD or MBE growth method to grow Si, Ge, GaAs, GaN and its superlattice, alloy materials, etc. Single layer semiconductor material or multilayer semiconductor structure material.

Contents of the invention

The object of the present invention is to propose a method for growing other semiconductor materials or structures using a novel InN material as a buffer layer or substrate material. Especially using InN semiconductor material as buffer layer or substrate material, using CVD, MOCVD or MBE to prepare InN/germanium or InN/silicon thin film on InN material as substrate or buffer layer, and can be extended to Si, Preparation of Ge, GaAs, GaN and its superlattice, alloy materials and other single-layer semiconductor materials or multi-layer semiconductor structure materials.

Technical solution of the present invention: InN material is used as substrate or buffer layer to prepare InN/germanium or InN/silicon thin film, InN material is used as substrate or buffer layer to prepare InN/germanium or InN/silicon thin film, and the thickness of InN material buffer layer is Above 100 nanometers, a single layer or n layers of germanium or silicon films are prepared on it, and the thickness of each layer of germanium or silicon films is above 50 nanometers. Especially for 100-200 nanometers, it is better to have 2-6 layers of germanium or silicon thin films.

The method of preparing InN/germanium or InN/silicon thin film using InN material as substrate or buffer layer, using InN material as substrate or first growing a layer of InN material on substrate material as buffer layer or support layer, and then growing Si , Ge, GaAs or GaN semiconductor single or multilayer materials. Conventional growth methods of semiconductor materials such as MOCVD, CVD, HVPE or MBE: a certain flow of N ₂ gas or H ₂ gas is introduced as a carrier gas during the growth process, and the growth temperature is controlled between 200°C and 1150°C. Source, metal source or other semiconductor material growth source, reaction synthesis growth (such as the reaction of metal germanium, silicon and chlorine gas) semiconductor material.

During the process: pretreatment: (a) put the InN material or the InN thin film material grown on other substrates into the growth chamber after cleaning outside the reaction chamber or directly without cleaning, and perform high-temperature baking, high-temperature corrosion, and plasma on the surface of the material. body cleaning or other methods, or without any surface treatment. (b) Or put any clean substrate material directly, after the substrate surface treatment in the reaction chamber of MOCVD, CVD, HVPE or MBE and other growth methods, grow a layer of InN thin film material as a buffer layer or support layer. Epitaxial growth: use InN material as the substrate, or use other semiconductor materials as the substrate, then grow a layer of InN material buffer layer or support layer on the substrate material, and finally use MOCVD,, Metal-organic sources (typically silane or germane), metal sources or other semiconductor material growth sources required by CVD, HVPE or MBE, continue to react to synthesize and grow other semiconductor thin film materials or semiconductor device structure materials. During the growth process, a certain flow rate of N ₂ gas or H ₂ gas was used as the carrier gas.

Mechanism and beneficial effect of the present invention: use new semiconductor InN material as substrate or new semiconductor InN thin film material grown on other substrates as buffer layer or support layer substrate material to re-grow other single-layer or multi-layer semiconductor materials, and use MOCVD , CVD, HVPE or MBE and other semiconductor material growth technologies, using the required metal-organic sources or other semiconductor material growth sources, the present invention realizes the growth of Ge and Si in the CVD system using InN thin film materials as substrates, especially using the new The semiconductor InN material or the new semiconductor InN film material grown on other substrates is used as a buffer layer or a support layer material. New semiconductor structures and new semiconductor phenomena have emerged. The thickness of the InN material buffer layer and the characteristics and applications of the formed germanium or silicon film structure are: especially the use of the not too large lattice mismatch ratio (9%) and the subtle difference in band gap between Ge(111) and InN (40meV) to obtain a heterostructure. The advantages of such heterostructures for producing heterojunction bipolar transistors (HBTs) as well as infrared light detectors are numerous. 1. The energy bandgap of InN and Ge matches, the difference is 40meV and the energy band offset matches. 2. The lattice mismatch is relatively small, and the mismatch between InN and Ge is 11.3%. 3. It is possible to have relatively good pn rectification characteristics.

Description of drawings

Fig. 1 is the XRD spectrum of the Ge thin film material grown on the InN/Al ₂ O ₃ substrate by MOCVD technology according to the present invention. It can be seen from the figure that the (0002) InN peak and the (111) Ge material peak as the substrate material prove that the InN material can be used as a substrate material for the growth of new semiconductors.

Fig. 2 is the low temperature (77K) photoluminescence (PL) spectrum of the Ge/InN sample grown in the present invention and the substrate InN. It can be observed that the position of the luminescence peak of the sample is basically the same as that of the standard InN sample, which indicates that the original InN substrate material layer does not disappear with the growth after epitaxial growth, but still remains. This is consistent with the XRD measurement results.

Fig. 3 is the EDS depth line scan curve of element Ge, In, N in the Ge/InN sample IV of the present invention, from the surface to the substrate direction, the atomic concentration of N has a tendency to increase slowly, and the atomic concentration of Ge and In is almost The maximum is reached at the same depth. This indicates that the amorphous film obtained by epitaxial growth may contain InGe alloy, which is due to the reaction of the adsorbed Ge atoms and part of the metal In enriched by _H2 treatment on the substrate surface. The existence, bonding status, and composition of InGe alloys must be confirmed by measurement methods such as XPS.

Detailed ways

Generally use InN/Al ₂ O ₃ substrate; InN material buffer layer to prepare InN/germanium or InN/silicon film, the thickness of each layer of germanium or silicon film is 100-200 nanometers, with 2-6 layers of germanium or silicon film.

The complete preparation scheme is: use InN material as the substrate or InN material grown on other substrates as the buffer layer or support layer material to grow other single-layer or multi-layer semiconductor materials, using MOCVD, CVD, HVPE or MBE, etc. Methods of growing semiconductor materials. Finally, within the temperature range of 200-1150°C, use metal-organic sources, metal sources or other semiconductor material growth sources required by MOCVD, CVD, HVPE or MBE growth technologies to react and grow other semiconductor thin film materials or semiconductor device structure materials. During the growth process, a certain flow rate of N ₂ gas or H ₂ gas was used as the carrier gas.

The present invention grows a low-temperature GaN buffer layer after high-temperature treatment on a (100) sapphire substrate, and then grows Ge, Si or other semiconductor thin film materials after growing InN. The optimal growth condition range is shown in Table 1 and Table 2.

Table 1. The range of growth conditions for growing other semiconductor materials on InN materials as substrates or support layers

Growth conditions\growth methods CVD MOCVD MBE other growing methods Growth temperature (℃) 200-1150 200-1150 100-700 100-1150 carrier gas N₂ or H₂ N₂ or H₂ N₂ or H₂ N₂ or H₂

Table 2 The process of growing Ge or silicon thin films on typical InN/Al ₂ O ₃ substrates by CVD

That is, on the InN/Al ₂ O ₃ substrate, use CVD technology to grow Ge or silicon thin film process, H ₂ flow 5-30SCCM, N ₂ flow 5-15 (SCCM); reaction chamber pressure: 20-100Pa growth temperature 300-600 ℃; the In source uses trimethyl indium, the Ga source uses trimethyl gallium, the gas flow rate is 5-10 SCCM, and InN can also be grown on the GaN/Al ₂ O ₃ substrate.

Claims (1)

1, the InN material is made the preparation method that substrate or resilient coating prepare the InN/ germanium film, it is characterized in that utilizing the InN material to do the also first InN material of on other substrate, growing of substrate and make resilient coating, in 200-1150 ℃ of growth temperature range, adopt CVD growing technology growth InN/ germanium, with the metal organic source is growth source, H ₂Flow 5-30SCCM, N ₂Flow 5-15SCCM; Reaction chamber pressure: 300-600 ℃ of 20-100Pa growth temperature; Trimethyl indium is adopted in the In source, and trimethyl gallium is adopted in the Ga source, and the flow of gas is 5-10SCCM; Feed the N of certain flow in the growth course ₂Gas or H ₂Gas is as carrier gas; The thickness of InN material resilient coating is more than 100 nanometers, prepares 2-6 layer germanium film thereon, and the thickness of every layer of germanium film is the 100-200 nanometer.

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