The present disclosure relates to an enhancement mode MISFET device. In some embodiments, the MISFET device has an electron supply layer located on top of a layer of semiconductor material. A multi-dielectric layer, having two or more stacked dielectric materials sharing an interface having negative fixed charges, is disposed above the electron supply layer. A metal gate structure is disposed above the multi-dielectric layer, such that the metal gate structure is separated from the electron supply layer by the multi-dielectric layer. The multi-dielectric layer provides fixed charges at interfaces between the separate dielectric materials, which cause the transistor device to achieve a normally off disposition.