Numerical Study On GaAs Based Metal-oxide-semiconductor High Electron Mobility Transistor With High K Oxide Gate Dielectric

With the development of semiconductor devices,the reduction in the size of the devices makes the gate oxide layer of the metal oxide field effect transistor thinner and thinner,and then resulting leakage current seriously degrades the reliability of the device.Traditional Si-based devices have been unable to meet the needs of the development of the device,Ga As is a potential candidate for replacing semiconductor Si due to its good electronic properties.At the same time,in order to increase the equivalent thickness of the gate oxide layer,Si O2 may be replaced with a high dielectric constant gate dielectric material,thereby reducing the quantum tunneling effect of the device to meet the needs of miniaturization.In this paper,the microstructure and physical properties of Ga As semiconductor/high dielectric constant oxide heterointerfaces are mainly explored by using density functional theory,which provides a theoretical basis for the preparation and design of Ga As semiconductor optoelectronic devices.This work mainly achieved the following research results:Firstly,we calculate the lattice constant,electronic density of state,charge distribution and energy band structure of Ga As semiconductor and the high dielectric constant oxides Ce O2,Ba Ti O3 and La Al O3 bulk materials.Secondly,We investigate the atomic structure and electronic properties of the heterojunction of binary oxide Ce O2 with semiconductor Ga As.The charge transfer and electron density of states are analyzed.The valence and conduction band offsets of the As/Ce interface and the As/O interface are larger than 1 e V,so the Ga As/Ce O2 heterojunction interface can also be used as a potential candidate for the transistor.Thirdly,as one of the most studied ABO3-type perovskite oxide ferroelectric materials,Ba Ti O3 has become a good gate oxide material due to its high dielectric constant and low dielectric loss.We calculate and analyze charge transfer and density of states of electrons and found that there is metallicity at the Ga As/Ba Ti O3 interface.The valence and conduction band offsets of the As/Ba O interface and the As/Ti O2 interface are not all larger than 1 e V,so those interfaces are not suitable for high electron mobility transistor designs.Fourthly,the La Al O3 atomic layer is arranged positively and negatively.To understand whether this structure will appear new physical phenomena,we calculate the Ga As/La Al O3 heterojunction interface.After analyzing their charge transfer and density of electron states,it is also found that there is metallicity at the interface,andthe valence and conduction band offsets at the As/La O interface and As/Al O2 interface are all larger than 1 e V,so this interface can also be used as high electron mobility transistor gate oxide candidate materials.