A gate structure for effective work function adjustments of semiconductor devices that includes a gate dielectric on a channel region of a semiconductor device; a first metal nitride in direct contact with the gate dielectric; a conformal carbide of Aluminum material layer having an aluminum content greater than 30 atomic wt. %; and a second metal nitride layer in direct contact with the conformal aluminum (Al) and carbon (C) containing material layer. The conformal carbide of aluminum (Al) layer includes aluminum carbide, or Al4C3, yielding an aluminum (Al) content up to 57 atomic % (at. %) and work function setting from 3.9 eV to 5.0 eV at thicknesses below 25 Å. Such structures can present metal gate length scaling and resistance benefit below 25 nm compared to state of the art work function electrodes.