Preparation And Characterization Of The InN Films

Semicondutor materials science and technology as the core technology of the modern high-tech, has been the driving force for the development of the information age. A variety of semicondutor devices and integrated circuits prepared by semicondutor materials promote the rapid development of information society. The succesful development of every new semiconduter materials are usually able to lead the new technological revolution and the development emerging industries. In recent years, Ⅲ-Ⅴ nitride semicondutor materials due to wide band gap、high eletron mobility speed、stable chemical property, gets the latest progress in UHF transistor swith, high-power transmission in the smart electric grids, high efficiency solar cells, high-precision chemialsensors, etc.Ⅲ-Ⅴ nitride semicondutor such as GaN, AlN, InN and their alloys, has broad application prospects in opical displays, optical storage, lighting and other areas. Which InN as an excellent semicondutor materials, more and more people know. InN at room temperature band gap is0.7eV, Ⅲ race nitride semiconductor materials with the highest mobility, electron drift velocity, and the smallest effective electron mass, which makes InN on the application of high-frequency, high-speed transistors advantage. In addition, due to the different band gap between InN and AlN (6.2eV), adjusting the In content of Al1-xInxN material, can be achieved band gap change, so you can be prepared from the infrared to the deep UV spectral range optoelectronic devices. Preparation of InN films has two difficulties:low dissociation temperature of InN material (600℃or more), high decomposition temperature of NH3(1000℃); lattice mismatch. At home and abroad the mainstream film preparation of InN has MOCVD, MBE, HVPE, magnetron sputtering technique. In this paper, we use the MOCVD technique preparate InN films on sapphire substrates,and research its nature under the conditions of different substrate temperature、Ⅲ-Ⅴ supply ratio.1. InN films were prepared on sapphire (0001) substrate by MOCVD method. High purity trimethyl indium [In(CH3)3](TMIn) was employed as In organometallic (OM) source, NH3as nitridizing agent and N2as carrier gas. The gowth temperature was varied from400to600℃,and the pressure in chamber was30Torr. The N/In supply ratio was20000/1. Considering various test results showed that the InN film growing in500℃temperature had better quality crystallization.when temperature was too low,the film growth rate was slow, quality of crystallization became poor. But with the growth temperature rise to600℃, the InN dissociation increase, with no film production.2. InN films were prepared on sapphire (0001) substrate by MOCVD method. High purity trimethyl indium [In(CH3)3](TMIn) was employed as In organometallic (OM) source, NH3as nitridizing agent and N2as carrier gas. The gowth temperature was500℃,and the pressure in chamber was30Torr. The N/In supply ratio was changed from15000/1-40000/1. X-ray diffraction (XRD) test results showed that with Ⅲ-Ⅴ supply ratio increase, the quality of films became better. When the ratio was30000/1, the growth quality was best. But when Ⅲ-Ⅴ supply ratio was than40000/1. there had no film production.