Analytical workload dependence of self-heating effect for SOI MOSFETs considering two-stage heating process

Dynamic self-heating effect(SHE)of silicon-on-insulator(SOI)MOSFET is comprehensively evaluated by ultrafast pulsed I-V measurement in this work.It is found for the first time that the SHE complete heating response and cooling response of SOI MOSFETs are conjugated,with two-stage curves shown.We establish the effective thermal transient response model with stage superposition corresponding to the heating process.The systematic study of SHE dependence on workload shows that frequency and duty cycle have more significant effect on SHE in first-stage heating process than in the second stage.In the first-stage heating process,the peak lattice temperature and current oscillation amplitude decrease by more than 25 K and 4%with frequency increasing to 10 MHz,and when duty cycle is reduced to 25%,the peak lattice temperature drops to 306 K and current oscillation amplitude decreases to 0.77%.Finally,the investigation of two-stage(heating and cooling)process provides a guideline for the unified optimization of dynamic SHE in terms of workload.As the operating frequency is raised to GHz,the peak temperature depends on duty cycle,and self-heating oscillation is completely suppressed.

Trigger mechanism of PDSOI NMOS devices for ESD protection operating under elevated temperatures

Trigger characteristics of electrostatic discharge(ESD)protecting devices operating under various ambient temperatures ranging from 30℃to 195℃are investigated.The studied ESD protecting devices are the H-gate NMOS transistors fabricated with a 0.18-μm partially depleted silicon-on-insulator(PDSOI)technology.The measurements are conducted by using a transmission line pulse(TLP)test system.The different temperature-dependent trigger characteristics of groundedgate(GGNMOS)mode and the gate-triggered(GTNMOS)mode are analyzed in detail.The underlying physical mechanisms related to the effect of temperature on the first breakdown voltage V_(T1)investigated through the assist of technology computer-aided design(TCAD)simulation.

Evolution of optical properties and molecular structure of PCBM films under proton irradiation

Low-energy proton irradiation effects on the optical properties and the molecular structure of phenyl-C_(61)-butyric acid methyl ester(PCBM)are studied in this work.The PCBM films are irradiated by 100-keV proton beams with fluences of 5×10^(12)p/cm^(2),5×10^(13)p/cm^(2),and 5×10^(14)p/cm^(2),respectively.The photoluminescence(PL)peaks of the post-irradiated PCBM films show a progressive decrease in the peak intensity as the proton fluences increase,which can be attributed to the deep defect levels induced by proton irradiation.Additionally,a slight blue-shift in the PL spectrum is also observed at a proton fluence of 5×10^(14)p/cm^(2).The underlying mechanism can be traced back to the lift of the lowest unoccupied molecular orbital(LUMO)level,which is caused by the attachment of methoxy radicals on ortho position of the phenyl ring in the post-irradiated PCBM structure.This work is of significance in understanding the radiation hardness and the damage mechanism of the PCBM film in radiation environments,which is essential before it is put into practical application in space.