SOI MOSFET自加热效应测试方法

为研究自加热效应对绝缘体上硅(SOI)MOSFET漏电流的影响,开发了一种可同时探测20 ns时瞬态漏源电流-漏源电压(Ids-Vds)特性和80μs时直流静态Ids-Vds特性的超快脉冲I-V测试方法。将被测器件栅漏短接、源体短接后串联接入超快脉冲测试系统,根据示波器在源端采集的电压脉冲的幅值计算漏电流受自加热影响的动态变化过程。选取体硅NMOSFET和SOI NMOSFET进行验证测试,并对被测器件的温度分布进行仿真,证实该方法用于自加热效应的测试是准确有效的,能为建立准确的器件模型提供数据支撑。采用该方法对2μm SOI工艺不同宽长比的NMOSFET进行测试,结果表明栅宽相同的器件,栅长越短,自加热现象越明显。

Test Method of Self-Heating Effects in SOI MOSFETs

An ultrafast pulse I-V test method to simultaneously detect transient drain-source current-drain-source voltage(Ids-Vds)characteristics at 20 ns and DC static Ids-Vds characteristics at 80μs was developed for investigating the influence of self-heating effects on leak current of silicon in insulator(SOI)MOSFETs.The device under test was connected to the ultrafast pulse test system in series after short connections of gate-drain and source-body.According to the amplitude of the voltage pulse collected by oscilloscope at the source,the dynamic change process of drain current under the influence of self-heating was calculated.Bulk-Si NMOSFETs and SOI NMOSFETs were selected for verification test,and the temperature distribution of the devices under test was simulated.It is proved that this test method is accurate and effective for testing self-heating effects and can provide data support for establishing accurate device models.The self-heating effects of NMOSFETs with different aspect ratios in 2μm SOI process were tested by the method.The results show that for devices with the same gate width,the shorter the gate length,the more obvions the self-heating phenomenon.