An AlN (insulator) MIS Hydrogen Sensor was created using plasma source molecular beam epitaxy (PSMBE) deposition on Si (111) and 6H-SiC. A Pd layer was deposited on top of the AlN film via magnetron sputtering technique utilizing a hard mask. Pd was chosen since H2 readily diffuses within its bulk, thus Pd acts not only as a metal electrode of the MIS structure, but also as a catalyst for hydrogen dissociation. To optimize the design structure several sensors with different AlN and Pd thickness have been developed. RHEED and XRD measurements show that AlN film is epitaxial on both Si (111) and 6H-SiC substrates. The sensors were characterized using capacitance versus voltage C(V) and I(V) measurements, at different frequencies ranging from 1kHz to 1 MHz. Shifts in the C-V and I-V curves occurred with the introduction of hydrogen in the chamber. The temperature, hydrogen partial pressure, effects of oxygen and hydrocarbon gases, insulator and metal thicknesses on sensor response were analyzed.