Property introduction
Indium phosphide (INP) is by the III group element indium (in) and V a family of phosphorus (P) compound and a III-V compound semiconductor. The crystal was dark gray, and the molecular weight was 145.8, the density was 4.78g/cm3, the microhardness of the micro hardness was 435 + 20/mm. With the zinc blende structure, lattice constants 5.869A. Under normal temperature, the band gap of 1.35eV, the direct transition band structure, the emission wavelength of 0.92 M. Mainly used in the manufacture of microwave oscillator, light emitting and laser device.
Existing level and development trend
Indium phosphide (InP) crystal was firstly introduced by Mulin in 1968 with the LEC drawing success. In the late 1970s, to InP substrate is fabricated in long wavelength lasers for the first time at room temperature lasing, the InP began to arouse people's attention. Since the 1980s, InP Single crystal growth technology matures, the continuous improvement of the crystal pulling apparatus, and to achieve automatic control, which have greatly promoted the improvement of InP Single crystal quality. At the same time, the practical application of InP in optical fiber communication engineering is based on InP, and the application of the single crystal is in the practical stage. A large number of studies have shown that the high electric field electron drift velocity () of InP is higher than that of GaAs (GaAs), which is suitable for manufacturing high speed and high frequency devices. In addition, the thermal conductivity of InP, solar energy conversion efficiency, radiation characteristics and so on are better than GaAs, suitable for the manufacture of integrated circuits, solar cells, etc.. Therefore, the research of OEIC and MISFET with Fe semi insulating InP substrate has been widely carried out. InP based HBT and HEMT devices, such as high-frequency and high-speed devices have been close to practical. Thus, InP has become another important electronic device material after GaAs, which will show its importance in the field of millimeter wave devices and integrated circuits. The stacking fault energy of InP single crystal is very low, and it is easy to produce twins, which makes it difficult to prepare InP single crystal. In the 90 "s, the mechanism, the thermal field distribution and the heat transfer during the process of crystal growth of InP single crystals have been studied, which promotes the growth of InP single crystal. Now Japan and the United States and other countries have produced 2in and InP 3in.
In the last few years, the new technology of InP single crystal has the following:
1.InP polycrystalline synthesis technology: at present, the synthesis of InP polycrystalline method with high pressure level of the (HPHB), high temperature gradient method (HPGF), solution diffusion method (SSI) and direct synthesis method. Because of the dissociation pressure of InP at the melting point of 27.5atm, the reaction temperature should be InP at the melting point of InP, and the vapor pressure of phosphorus should be 27.5atm at 1070. But in fact, due to high pressure, it is difficult to control the balance, the general synthesis of the pressure is slightly lower than 27.5atm, for the 20 ~ 25atm. The synthesis temperature was 1000 ~ 1100, and both HPHB and HPGF were in this situation. With these two kinds of method for the synthesis of polycrystalline InP low purity, the main reason is due to serious silicon contamination produced by high temperature quartz boat, reducing the purity of polycrystalline InP, usually the low temperature (77K) migration rate of 15000 to 40000cm^{2}/v.s, the carrier concentration is 2 ~ 30 x 10^{15}cm^{-3}. Now people use the boat to reduce the boron nitride silicon contamination, the synthesis effect is good. The reaction temperature is very low when the solution diffusion method (SSI) is synthesized, which is usually 900 ~ 800, and the carrier concentration is 3 * 79000cm^{2}/v.s ~ 3 * 10^{4}cm^{-3}, the migration rate is 126000 ~ 10^{15}cm^{-3}. But because the speed of this synthetic method is very slow, the synthesis of polycrystalline InP is very small, generally do not use this method for the synthesis of crystal pulling. The direct synthesis of the furnace is divided into the furnace of the phosphorus injection method and liquid phosphorus cover method. The advantages of the method of the furnace injection method are rapid synthesis and high purity. InP purity is high, but this method is not high, the actual application is not much.
Current status of 2.InP single crystal growth technology:
InP single crystal growth has two kinds of high pressure liquid seal direct pull (HPLEC) and vertical temperature gradient freezing (VGF). One of the commonly used is the high pressure liquid seal. HPLEC and HPLEC have their advantages and disadvantages, and the VGF method has been more mature, the main drawback is that the growth of single crystal dislocation density. But in recent years, it has been improved by HPLEC, which greatly reduces the longitudinal temperature gradient in the growth process, thereby reducing the dislocation density of the growth of InP single crystals, the advantages of VGF method is that the growth process of the vertical temperature gradient is small, the growth of InP single crystal dislocation density is low.
Development trend of 3.InP single crystal growth technology:
In order to obtain high quality InP single crystal, the synthesis of the furnace injection is a promising method. According to the present conditions, the room temperature carrier concentration of high purity InP will reach 5 * 10^{14}cm^{-3}, the migration rate should be about 5000cm^{2}/v.s. EPD will be a major task for the preparation of single crystal InP. VCZ technology is one of the main methods of producing low InP EPD single crystals, and it will be the most promising method in the high pressure liquid sealing.
In the preparation of InP crystal, Japan is in the leading position in the world, which is expressed as the result of the publication, the advanced technology and the high performance of the material. American InP crystal preparation technology was less than that of japan. In addition, in the North Atlantic Treaty Organization (NATO) countries, the majority of Companies in the GaAs and InP manufacturing have a positive research plan, France and several German companies are active in InP research, France is committed to the work of the InGaAs/P structure for the integration of optical structure is also a great ability to understand this technology. Progress has also been made in the field of compound semiconductor materials.
Investment status
The United States in the 1986 ~ 1990 fiscal year on semiconductor materials and microelectronic circuits, the key technology of a total investment of 2100000000 U. S. dollars. In 1990, the United States for the first time proposed the key technology program (1990) will be InP, GaAs, and other compounds semi - Guide