Investigation of Mo/Ti/AlN/HfO2 High-k Metal Gate Stack for Low Power Consumption InGaAs NMOS Device Application

Use of the Mo/Ti/AlN/HfO2 metal/dielectric stack to increase the permittivity of HfO2 for low power consumption InGaAs-based MOSFET is investigated in this letter. The dielectric constant of HfO2 was found to increase by 47%, from 17 to 25, after Ti doping without affecting the interface trap density around the mid-gap of the MOSCAPs. A strong inversion behavior with low leakage current for the MOSCAP was also observed. The gate voltage needed to tune the Fermi level of InGaAs channel was found to be smaller for the Ti-doped HfO2 sample as compared with the sample with un-doped HfO2. The increase of the dielectric constant of HfO2 after Ti doping combined with the use of Ti gate metal, which has the work function level near the conduction band edge of InGaAs, makes the proposed Mo/Ti/HfO2 (Ti) stackideal for future lowpower consumption InGaAs-based NMOS applications.