The time and temperature dependence of threshold voltage shift under positive-bias stress（PBS） and the following recovery process are investigated in amorphous indium-gallium-zinc-oxide（a-IGZO） thin-film transisto...The time and temperature dependence of threshold voltage shift under positive-bias stress（PBS） and the following recovery process are investigated in amorphous indium-gallium-zinc-oxide（a-IGZO） thin-film transistors. It is found that the time dependence of threshold voltage shift can be well described by a stretched exponential equation in which the time constant τ is found to be temperature dependent. Based on Arrhenius plots, an average effective energy barrier Eτ stress= 0.72 eV for the PBS process and an average effective energy barrier Eτ recovery= 0.58 eV for the recovery process are extracted respectively. A charge trapping/detrapping model is used to explain the threshold voltage shift in both the PBS and the recovery process. The influence of gate bias stress on transistor performance is one of the most critical issues for practical device development.展开更多
The electrical instability behaviors of amorphous-indium-gallium-zinc-oxide （a-IGZO） thin-film transistors （TFTs） under ultraviolet （UV） illumination are studied. As UV radiation dosage increases, the turn-on vo...The electrical instability behaviors of amorphous-indium-gallium-zinc-oxide （a-IGZO） thin-film transistors （TFTs） under ultraviolet （UV） illumination are studied. As UV radiation dosage increases, the turn-on voltage of the TFT shows continuous negative shift, which is accompanied by enhanced degradation of sub-threshold swing and field-effect mobility. The electrical instability is caused by the increased carrier concentration and defect states within the device channel, which can be further attributed to additional oxygen vacancy generation and ionization of oxygen vacancy related defects upon UV illumination, respectively. Furthermore, the performance of the a-IGZO TFT treated with UV radiation can gradually recover to its initial stste after long-time storage.展开更多
The influence of white light illumination on the stability of an amorphous In GaZnO thin film transistor is investigated in this work. Under prolonged positive gate bias stress, the device illuminated by white light e...The influence of white light illumination on the stability of an amorphous In GaZnO thin film transistor is investigated in this work. Under prolonged positive gate bias stress, the device illuminated by white light exhibits smaller positive threshold voltage shift than the device stressed under dark. There are simultaneous degradations of field-effect mobility for both stressed devices, which follows a similar trend to that of the threshold voltage shift. The reduced threshold voltage shift under illumination is explained by a competition between bias-induced interface carrier trapping effect and photon-induced carrier detrapping effect. It is further found that white light illumination could even excite and release trapped carriers originally exiting at the device interface before positive gate bias stress, so that the threshold voltage could recover to an even lower value than that in an equilibrium state. The effect of photo-excitation of oxygen vacancies within the a-IGZO film is also discussed.展开更多
基金Project supported by the National Basic Research Program of China(Grant Nos.2011CB301900 and 2011CB922100)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The time and temperature dependence of threshold voltage shift under positive-bias stress（PBS） and the following recovery process are investigated in amorphous indium-gallium-zinc-oxide（a-IGZO） thin-film transistors. It is found that the time dependence of threshold voltage shift can be well described by a stretched exponential equation in which the time constant τ is found to be temperature dependent. Based on Arrhenius plots, an average effective energy barrier Eτ stress= 0.72 eV for the PBS process and an average effective energy barrier Eτ recovery= 0.58 eV for the recovery process are extracted respectively. A charge trapping/detrapping model is used to explain the threshold voltage shift in both the PBS and the recovery process. The influence of gate bias stress on transistor performance is one of the most critical issues for practical device development.
基金Supported by the Key Industrial R&D Program of Jiangsu Province under Grand No BE2015155the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Fundamental Research Funds for the Central Universities under Grant No 021014380033
文摘The electrical instability behaviors of amorphous-indium-gallium-zinc-oxide （a-IGZO） thin-film transistors （TFTs） under ultraviolet （UV） illumination are studied. As UV radiation dosage increases, the turn-on voltage of the TFT shows continuous negative shift, which is accompanied by enhanced degradation of sub-threshold swing and field-effect mobility. The electrical instability is caused by the increased carrier concentration and defect states within the device channel, which can be further attributed to additional oxygen vacancy generation and ionization of oxygen vacancy related defects upon UV illumination, respectively. Furthermore, the performance of the a-IGZO TFT treated with UV radiation can gradually recover to its initial stste after long-time storage.
基金supported by the State Key Program for Basic Research of China(Grant Nos.2011CB301900 and 2011CB922100)the Priority Academic Program Development of Higher Education Institutions of Jiangsu Province,China
文摘The influence of white light illumination on the stability of an amorphous In GaZnO thin film transistor is investigated in this work. Under prolonged positive gate bias stress, the device illuminated by white light exhibits smaller positive threshold voltage shift than the device stressed under dark. There are simultaneous degradations of field-effect mobility for both stressed devices, which follows a similar trend to that of the threshold voltage shift. The reduced threshold voltage shift under illumination is explained by a competition between bias-induced interface carrier trapping effect and photon-induced carrier detrapping effect. It is further found that white light illumination could even excite and release trapped carriers originally exiting at the device interface before positive gate bias stress, so that the threshold voltage could recover to an even lower value than that in an equilibrium state. The effect of photo-excitation of oxygen vacancies within the a-IGZO film is also discussed.
