JP4342573B2 - Method for growing compound semiconductor thin films - Google Patents

Description

  The present invention relates to a technique for growing an epitaxial crystal of a III-V compound semiconductor using nitrogen as a group V material by metal organic chemical vapor deposition (MOCVD).

When III-V compound semiconductor epitaxial crystals using nitrogen as the group V material are grown by MOCVD, ammonia (NH ₃ ), the nitrogen material, is decomposed more efficiently than phosphine (PH ₃ ) and arsine (AsH ₃ ). Is extremely low. For this reason, nitride systems generally require higher temperature growth and higher V / III ratio growth than other III-V compound semiconductors. High-temperature growth causes evaporation of group III materials and dopant materials, making it difficult to grow materials containing aluminum (Al) and indium (In), which have higher vapor pressures than gallium (Ga). On the other hand, if the growth temperature is lowered, NH ₃ is not decomposed, so a high V / III ratio growth is required, and excess NH ₃ forms a complex with a group III organic material or dopant organic material, preventing crystal growth. Low temperature crystallinity has been considered difficult.

In epitaxial crystal growth by MOCVD, when growing high quality nitride using NH ₃ which is a general material, high temperature growth of about 1000 ° C. is required. However, growth of InGaN with a high In composition is difficult at high temperature growth exceeding 1000 ° C., and growth of InGaN thin film with an In composition of 10% or more requires low temperature growth at 780 ° C. or less. However, at a low temperature of 780 ° C. or lower, NH ₃ is not sufficiently decomposed and it is difficult to obtain an InGaN thin film having a high In composition even if a large amount of material is consumed.

In order to solve the above-mentioned problems, in the present invention, TEA is mixed with NH ₃ to increase the decomposition efficiency of nitrogen through a mutual chemical reaction process, and achieve epitaxial crystal growth of GaN and InGaN thin films with a high In composition at a low temperature of 600 ° C. is doing.

  By using the epitaxial crystal growth method according to the present invention, GaN and an InGaN thin film having a high In composition can be obtained at a low temperature of 600 ° C.

  Embodiments will be described below with reference to the drawings.

NH ₃ , TEA, and triethylgallium (TEG) are used for epitaxial crystal growth of GaN thin films. Sapphire is used for the substrate, and the temperature is raised to 800 ° C to increase the adhesion between the substrate and the GaN thin film before growth. Crystals were grown at a temperature of 600 ° C. for 15 minutes with the material supply amounts shown in Table 1. The growth was terminated by stopping the supply of TEG, and then the temperature was raised to 800 ° C. while maintaining the flow rates of NH ₃ and TEA for the purpose of adjusting the surface state, and the temperature was lowered after holding for 30 minutes. In the photoluminescence spectrum of the obtained thin film shown in FIG. 1, light emission was observed at 375 nm peculiar to GaN, and the growth of the GaN thin film was confirmed.

NH ₃ and TEA, triethylgallium (TEG), and triethylindium (TMI) are used for epitaxial crystal growth of the InGaN thin film. As the substrate, GaN grown on sapphire was used, and a crystal was grown for 10 minutes at a growth temperature of 600 ° C. with the material supply amount shown in Table 1. The obtained InGaN thin film was confirmed to have an In composition of 60% and a Ga composition of 40% by secondary ion mass spectrometry (SIMS) shown in FIG.

  Material supply amount used in the present invention

It is a figure of the photoluminescence spectrum of a GaN thin film. It is a figure of the SIMS profile of an InGaN thin film.

Claims (2)

In epitaxial crystal growth of GaN thin films on III-V compound semiconductor thin film laminated wafers by metalorganic vapor phase epitaxy using triethylgallium (TEG), ammonia, and triethylamine (TEA) as organometallic materials, ammonia and triethylamine (TEA) mutual chemical reaction process decomposes the V material, the crystal growth method according to claim Rukoto grown GaN thin film at a growth temperature of 600 ° C for). In epitaxial crystal growth of InGaN thin films on III-V compound semiconductor thin film laminated wafers by metal organic vapor phase epitaxy using triethylgallium (TEG) and triethylindium (TEI), ammonia, and triethylamine (TEA) as organometallic materials decomposes the V material by mutual chemical reaction step of ammonia and triethylamine (TEA), at a growth temperature of 600 ° C, crystal growth method in composition characterized Rukoto grown InGaN thin film of more than 10 percent.

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