Using non-planar (3D) transistor architectures like FinFETs and Gate-all-around (GAA) FETs is a major advancement in the electrical industry. Multiple considerations have shown that 3D transistors are replacing 2D planar transistors. Short channel effects may be mitigated by using 3D transistors to adjust channel area. However, silicon dioxide (SiO2) dielectric performance limits device scaling. FinFETs using HK-MG materials can better manipulate channel electrons, improving device performance. In FinFET technology, HK-MG materials are compatible with traditional manufacturing methods, meeting the need for a replacement to SiO2. Hafnium and Titanium oxides are promising high-k dielectrics for submicron electronics. This study uses Ashby's methods to choose high-k metal gate (HK-MG) materials for FinFETs. The goal is to simulate energy band-gap, electric field distribution, charge density, and surface potential to prove these materials can replace SiO2.FinFET with HK-MG improves band-gap Energy (Eg) in addition to Electric Field Density, Surface Potential and Charge Density Distribution. With the use of High-k materials the corresponding bandgap energy is reduced. With Si. Ge, GaAs, InN and GaN the Eg (eV) was reduced to about 0.613eV, 0.08eV, 0.879eV, 1.932eV and 1.148eV respectively. As a result, GaAs, InN, and GaN as metal gate (MG) materials are more appropriate candidates than classic Si materials. High-k dielectric oxide (HK) materials and Metal Gates (MG) are examined for energy band-gap, electric field distribution, charge density, and surface potential in this work. Semiconductors with better electron mobility than silicon are better for high-frequency applications. GaN's high mobility and power density, which dissipates heat from tiny components, are noteworthy.