Damage law and mechanism of total dose of PDSOI transistors with different channel lengths caused by backgate bias

Abstract

BackgroundTotal dose effect of silicon-on-insulator (SOI) devices can be reinforced through the back gate port, hence the device parameter degradation caused by irradiation can be compensated by applying back-gate bias voltage using the positive back gate coupling effect. However, previous studies have focused more on the effects of back-gate bias voltage applied after irradiation on radiation damage, and rarely involved the regulation of back-gate bias voltage applied during irradiation on the physical process of radiation introduced into the trap charge.PurposeThis study aims to investigate the regulation and mechanism of the back gate bias on the buried oxide (BOX) radiation-induced trap charge.MethodsBased on the transistor transfer characteristic curve, the radiation damage laws of partially depleted silicon-on-insulator (PD SOI) metal oxide semiconductor field effect transistors (MOSFETs) of different sizes under different back gate biases were tested by extracting the trap charge density in the BOX layer. TCAD (Technology Computer Aided Design) device simulation was performed to investigate the mechanism of radiation damage.ResultsThe test results show that the damage of long channel transistors is significantly enhanced by applying back-gate bias during the irradiation process. When the back-gate bias is applied to short channel transistor, the distribution and intensity of electric field in BOX layer are different from that of long channel transistor, hence is affected by the source drain voltage whilst the influence of source drain voltage on long channel transistor can be ignored.ConclusionsBack gate bias and source drain voltage jointly affect the distribution and intensity of electric field in BOX layer of PD SOI MOSFETs, and the damage of long channel transistors is significantly enhanced by applying back-gate bias during the irradiation process.

Keywords

• silicon-on-insulator
• buried oxide
• back gate control
• total ionizing dose effect