To promote the research on the growth of high-quality InN films attractive to the application for both optical and electronic devices, the pressurized-reactor metalorganic-vapor-phase epitaxy (PR-MOVPE) system which can overcome the high equilibrium-vapor-pressure of nitrogen between solid and vapor phases is originally developed. In addition to this system, the N-polar growth technique developed in the growth of GaN is introduced. As a result, the dense InN films with atomic steps are successfully grown. From the struggle of the research on high quality InN, the subject of the phase purity is also arisen. The pole figure measurements make the growth condition for a pure InN with a wurtzite structure. The phase purity is almost determined by the growth temperature. These results will pave the way to high-quality InN.