Atomic Layer Deposited Al2O3 films on hydrogen-terminated 6H-SiC(0001) were annealed in hydrogen atmosphere and characterized by admittance spectroscopy measurement and photoelectron spectroscopy (PES). The resultant density of interface trap (D-it) from admittance spectroscopy measurement is reduced near mid gap, but increases strongly towards the conduction band edge. Systematic PES measurements show that hydrogen annealing introduces Si4+ as a new component besides Si-0 and Si+. Using different electron escape depths for photon electrons, depth profiling of Si in its different oxidation states was performed. The result indicates the formation of a top SiO2 layer and a rougher interfacial layer containing more Si+ and Si4+ which could be responsible for the strong increase of Dit just below the conduction band edge.