Improved Interfacial Characteristics Of GaAs MOS Devices By Using NH₃-plasma Treated Interfacial Passivation Layer

As the development of the semiconductor industry and the miniaturization of the device,the Si-MOSFET COMS technology is tending to its theoretical limit.ThenGaAs has attracted a lot of attention for its high electric mobility and wide band gap,but when we enjoy the convenience bring by GaAs we also face the problem bring by it,e.g.the native oxides of GaAs at the interface of the substrate will lead a high interface-state density and pinning of Fermi-level.In order to solve these problems,the passivation of GaAs and the interfacial passivation layer?IPL?has been widely studied to improve the interfacial's property of the device.Here the GaAs-MOS has been fabricated with a stack gate dielectric the ZnON has been chosen as IPL and the Hf Ti ON as high k material,and the NH₃ plasma treatment has been carry out after the deposition of the ZnON.As a result,better interfacial and electric have been obtained for the GaAs MOS capacitor with ZnON IPL plus NH₃-plasma treatment as compared to is counterpart without IPL or without plasma treatment on the IPL.And the XPS show the ZnON IPL can effectively blocking the in-diffusing of O atoms and Ti atoms from Hf Ti ON to substrate to suppress the producing of the native oxides.And then the lanthanun has been incorporated to the IPL to further improve the property of the sample.The results show the samples with La incorporated IPL has achieved greater accumulation capacitance and the greater value of k and a lower leakage current.These are closely related to the large dielectric constant of La-compounds,and the wide band gap of la-based oxide or oxynitride can reduce the thermionic emission and the gate leakage current.In addition,the result of XPS show that the NH₃ plasma treated ZnLaON IPL can also reduce the native oxides on the interface of Ga As.The NH₃-plasma treatment has been confirm can effectively improve the property of the interficial.So the process conditions of NH₃ treatment has been discussed to find the most suitable process conditions.Here wediscussed the different treating time of the NH₃ plasma treatment after the deposition of the ZnLaON IPL.The result shows that the performance of the device improved gradually with the increase of NH₃-plasma treatment time from 0 to 10 mins,then become worser as the time of the NH₃-plasma treatment increase from 10 to 20 mins.The results of AFM show that the long NH₃-plasma treatment can deteriorate the quality of the ZnLaON film.