InN material is a kind of excellent semiconductor materials and plays an important role in photoelectron field. Due to the huge application potential and the secrets of the characters having been revealed, the InN material has already been one of the most attractive materials in recent two years.

InN film was synthesized by ammoniating indium film on Si (111) substrates, and there are two major problems in producing InN film currently.

The dissociation temperature of InN material is low and it dissociates at 600 ℃ around, while the decomposition temperature of NH3 is around 1000℃. This is a contradictory condition in the course of producing InN. The commonly used methods to manufacture InN currently are MBE, HVPE, magnetron sputtering and MOCVD.

The other problem is it is hard to find appropriate substrate. Single crystal is very difficult to get, so the first step is to get heter epitaxy InN film, and this requires dealing with the issue of lattice matching in crystal growth.

Indium nitride is one of the Ⅲ-Ⅴ nitride semiconductors with a direct band gap of 0.7-1.0eV [1-4]. It has the smallest effective electron mass of all the group-Ⅲ nitrides, which leads to high mobility and high saturation velocity, and a large drift velocity at room temperature [5-8]. Due to these properties of InN, it has potential applications in optoelectronic devices, such as LEDs and high efficiency solar cells, as well as high frequency (high power) electronic devices. In resent years, much effort has been made to grow InN film by various methods such as metal organic chemical vapour deposition (MOCVD), molecular beam epitaxy (MBE), and reactive sputtering. In this letter, We report the synthesis of InN film by ammoniating In/Si thin film with radio frequency magnetron sputtering.

The In film was deposited on Si (111) using a JCK-500A r.f. magnetron sputtering system. The conditions of sputtering were as follows: the backgroud pressure was 4.0×10-4 Pa; The distance between targets and substrates was 8 cm; the pressure of Ar (99.999%) was 3 Pa. After 30s, N2 (99.999%) instead of Ar was introduced to the chamber. The pressure of N2 was 3 Pa. The In film was grown by sputtering an indium (99.99%) target with r.f. power of 150W for 15 min.

The InN thin film was synthesized by ammoniating the In thin film in an open quartz tube inside a horizontal quartz tube. Firstly, the samples were placed into the reaction system when the temperature of the system was increased to 700℃. Secondly, N2 was introduced into the system for 5 min to expel air and then NH3 (99.999%) with a flux of 500ml/min was introduced into the system for 2 hours. After nitridation, the quartz boat was quickly cooled down to room temperature in the flow of super pure N2 gas (99.999%).

In conclusion, structural and compositional characterization were performed using X-ray diffraction (XRD, Rigaku D/max -rB Cu K), Fourier transform infrared (FTIR, TENSOR27) and X-ray photo-electron spectroscopy (XPS, MICROLAB MK Ⅱ).

In summary, InN film has been grown on Si (111) by nitriding indium film under a flow of ammonia at 700℃ for 2 hours. The samples have investigated by XRD, FTIR, XPS. XRD and FTIR reveal that InN we produced has a hexagonal structure with lattice constants a=0.354 nm and c=0.5705 nm. XPS confirms the formation of bonding between In and N.