Novel structure of deep trench capacitor with higher breakdown and higher capacitance density for Low Dropout Voltage regulator

This paper discusses a novel structure of deep trench capacitor with breakdown voltage of 10V and capacitance density of 527nF/mm², serving for Low Dropout Voltage regulator in IC power management. The structure is presented using 3D & 2D Sentaurus Synopsys simulation, with RIE etching and high quality LPCVD is deployed on the equivalent process. Higher breakdown is achieved by choosing low-k, high band-gap dielectric material. Higher capacitance density is achieved by implementing deeper trench using state of the art etching technology with aspect ratio of 1:50. After forming trench in a 75 μm deep trench in an Arsenic doped silicon substrate, an oxide growth of 5 nm is presented following by continuous LPCVD of 0.5 μm polysilicon and 10 nm oxide, stacked 3 times. The LPCVD polysilicon is arsenic-doped to form a good electric conductivity and to reduce ESR. A further study on RF performance shows an effective result on ESR and ESL.