MOSFET器件质量与可靠性的互补表征体系研究

Study of Complementary Characteristic Systems for the Quality and Reliability of MOSFET Devices

尺寸缩小效应会导致金属-氧化物半导体场效应晶体管(Metal-Oxide-Semiconductor Field-Effect Transistor,MOSFET)的性能变化,引发质量与可靠性等问题,进而制约微电子器件性能和使用寿命。对插入厚度为5 nm的Al_(2)O_(3)帽层结构的nMOSFET器件进行电学性能和低频噪声性能测试,并提取了阈值电压、栅极关态电流、亚阈摆幅、载流子迁移率及迁移率衰减系数等参数。通过分析栅极电压噪声功率谱密度和栅极缺陷密度,建立了MOSFET器件电学表征方法和低频噪声表征方法的互补表征体系。结果表明,栅极结构中插入5 nm Al_(2)O_(3)帽层能有效地调制器件的阈值电压,关态泄漏电流密度降低了97%,器件的输出功率提高了26%;但由于Al_(2)O_(3)帽层的插入,在栅极氧化物界面处引入了陷阱,导致载流子在界面处的散射几率增大,迁移率降低了49%。

The size downscaling effect of metal-oxide-semiconductor field-effect transistor(MOSFET)will lead to performance changes,quality and reliability problems,and affect the performance and lifetime of microelectronic devices.The electrical performance and low-frequency noise behaviors of nMOSFET devices with 5 nm Al2O3 capping layer are investigated at room temperature.The threshold voltage,gate off-state leakage current,sub-threshold swing,carrier mobility and mobility attenuation coefficient are extracted.By analyzing the power spectral density of the gate voltage noise,the oxide trap density in the gate layer is extracted,and a complementary characterization system of electrical properties method and low-frequency noise method of MOSFET devices is established.The conclusions indicate that the threshold voltage of the nMOSFET device can be modulated effectively by inserting 5 nm Al_(2)O_(3) capping layer.Moreover,the off-state leakage current density is reduced about 97%,and the output power of the devices increased about 26%.However,due to the insertion of Al_(2)O_(3) capping layer,oxide trap exist in the interface of the gate,which increases the scattering probability of the carrier at the interface,resulting in a 49% reduction in mobility.