Abstract MOVPE growth and Mg doping of InGaN films are studied to develop technologies for the InGaN-based solar cell. By optimizing growth temperature and the TMI/(TMI+TEG) molar ratio, InGaN films with an In content up to 0.37 are successfully grown without phase separation and metallic In incorporation. It is found that the In composition in the InGaN films is governed by growth temperature, and the TMI/(TMI+TEG) molar ratio has very small effect on the composition change. InGaN films doped with Mg using CP 2Mg show the compensation effect of carriers and those with an In content up to 0.2 show p-type conduction. The film with an In content of 0.37 shows phase separation when the CP 2Mg/(TMI+TEG) molar ratio exceeds 0.05, indicating that Mg atoms incorporated have a significant effect on the crystal growth of InGaN.