Direct Evaluation of Self-Heating Effects in Bulk and Ultra-Thin BOX SOI MOSFETs Using Four-Terminal Gate Resistance Technique

We demonstrate clear self-heating effects (SHEs) of bulk and silicon-on-insulator (SOI) MOSFETs for various SOI/buried oxide (BOX) thicknesses including ultra-thin 6 nm BOX, which was not detected by the ac conductance method, using the four-terminal gate resistance technique. We clarify that the SHE in bulk MOSFETs originates from the degradation of thermal conductivity in a heavily doped well region. The strong chip-temperature dependence of the SHE was observed only in bulk MOSFETs. As results of the chip temperature-dependent SHE of bulk devices and the SHE suppression by BOX thinning, the device temperature of ultra-thin BOX SOI MOSFETs is close to that of bulk MOSFETs at an elevated chip temperature, which suggests the thermal advantage of extremely thin BOX structures.

我们利用四端栅极电阻技术，展示了体硅和绝缘体上硅（SOI）金属 - 氧化物 - 半导体场效应晶体管（MOSFET）在包括超薄6纳米埋氧层（BOX）在内的各种SOI/BOX厚度下明显的自热效应（SHE），而这种效应是交流电导法无法检测到的。我们阐明体硅MOSFET中的自热效应源于重掺杂阱区热导率的降低。仅在体硅MOSFET中观察到自热效应强烈依赖于芯片温度。由于体硅器件的自热效应依赖于芯片温度以及BOX减薄对自热效应的抑制，在芯片温度升高时，超薄BOX SOI MOSFET的器件温度接近体硅MOSFET的温度，这表明了极薄BOX结构在散热方面的优势。