In this work metalorganic chemical vapor phase epitaxy (MOVPE) growth and characterization of AlInN in the whole compositional range and the impact on the development of field effects transistors (FET) structures will be presented. Due to the large difference in the lattice parameters of the binaries AlN and InN the growth of AlInN with high indium concentrations is ambitious, and first the growth conditions for the alloy will be discussed. An experimental phase diagram and corresponding theoretical calculations will be displayed. The critical layer thickness of AlInN on GaN has been experimentally determined. Relaxation of the AlInN-layer has a strong influence on the sample morphology. At indium concentration exceeding 30% an polarization induced hole gas is expected at the AlInN/GaN interface from theoretical calculations, but no p-channel conductivity could be confirmed. The absence of the two dimensional hole gas will be discussed.