Owing to its good tolerance to radiations, its high light absorption and its Indium-composition-tuned bandgap, the Indium Gallium Nitride (InGaN) ternary alloy is a good candidate for high--efficiency--high--reliability solar cells able to operate in harsh environments. Unfortunately, InGaN p-doping is still a challenge, owing to InGaN residual n-doping, the lack of dedicated acceptors and the complex fabrication process itself. To these drawbacks can be added the uneasy fabrication of ohmic contacts and the difficulty to grow the high-quality-high-Indium-content thin films which would be needed to cover the whole solar spectrum. These drawbacks still prevent InGaN solar cells to be competitive with other well established III-V and silicon technologies. In this communication, a new Metal-IN (MIN) InGaN solar cell structure is proposed, where the InGaN p-doped layer is removed and replaced by a Schottky contact, lifting one of the above mentioned drawbacks. A set of realistic physical models based on actual measurements is used to simulate and optimize its behavior and performance using mathematically rigorous multi-criteria optimization methods, aiming to show that both efficiency and fabrication tolerances are better than the previously described simple InGaN Schottky solar cell.