Barrier height control of metal/n-In0.2Ga0.8N with an ultrathin interfacial layer

In this paper the barrier height control of n-type InGaN has been demonstrated by a simple physics based unified model. Metal induced gap states (MIGS) model for metal-semi-conductor contact has been extended to metal-insulator-semiconductor (MIS) contact for unpinning of Fermi level and low contact resistivity formation. Metal/n-In_0.2Ga_0.8N contact is strongly pinned with a pinning factor value of 0.28. This work has improved the pinning factor from 0.28 to almost closer to 1 by inserting an ultrathin GeO₂ (2 nm) insulator layer and by varying this layer thickness, density of interface electronic states has been controlled which modulated the barrier height. Finally an excellent ohmic contact has been formed by using Cu as the metallic contact with contact resistivity as low as 1.4×10^-8 Ω-cm² at 600K.