Influence of an Insulator Layer on the Charge Transport in a Metal/Insulator/n‐AlGaN Structure

In this work, a parametric study revealing the impact of metal‐insulator‐semiconductor (MIS) structure in improving the electron injection between the n‐AlGaN layer and the electrode metal is conducted. After inserting an insulator at the surface between the n‐AlGaN layer and the electrode metal, the energy band bending of the thin insulator manipulates the conduction band barrier height between the electrode and the n‐AlGaN layer, which enables the electrons to more efficiently tunnel through the thin insulator barrier. As a result, the electrical characteristics for the devices are significantly improved if the MIS structure is optimized. Furthermore, the impact of the affinity, the relative dielectric constant, and the bandgap for the insulator on the electron injection is investigated. Meanwhile, it is found that the electron injection is sensitive to the thickness and the length for the insulator. Detailed analysis regarding the electron transport and the device physics are reported in this work.