Lee Chang-Chun, Liu Chuan-Hsi, Chen Zih-Han, Tzeng Tzai-Liang
J Nanosci Nanotechnol. 2015 Mar;15(3):2173-8. doi: 10.1166/jnn.2015.10227.
In this research, an n-type metal-oxide-semiconductor field effect transistor (nMOSFET) device with a SiGe channel exerted by the combination of a contact etching stop layer (CESL) and silicon germanium (Si1-xGe(x)) channel stressors is proposed. To explore the foregoing mechanical effect on the stress distribution of nMOSFETs within the channel region, a process-oriented simulated technique is adopted for the concerned nMOSFET device. The loading sources are a 1.1 GPa tensile CESL (t-CESL) and a SiGe channel structure constructed with 0%, 22.5%, and 25%, germanium (Ge) mole fractions. The results of the simulation show that the stress components of the Si1-xGe(x) channel evidently increase when the Ge mole fraction within a Si1-xGe(x) layer is increased. A pulling force exerted on the protruding gate structure by the CESL layer that causes dominant bending deformation and channel stress variation behaviors is a major reason for this phenomenon. Therefore, the degree of bending effect caused by the protruding gate structure is concluded as being the key to determining the trends and stress magnitudes of the Si1-xGe(x) device channel.
在本研究中，提出了一种具有SiGe沟道的n型金属氧化物半导体场效应晶体管（nMOSFET）器件，该沟道由接触蚀刻停止层（CESL）和硅锗（Si1-xGe(x)）沟道应力源共同作用形成。为了探究上述机械效应在沟道区域内对nMOSFET应力分布的影响，针对所关注的nMOSFET器件采用了面向工艺的模拟技术。加载源为1.1 GPa的拉伸CESL（t-CESL）以及锗（Ge）摩尔分数分别为0%、22.5%和25%的SiGe沟道结构。模拟结果表明，当Si1-xGe(x)层内的Ge摩尔分数增加时，Si1-xGe(x)沟道的应力分量明显增加。CESL层对突出栅极结构施加的拉力导致了主要的弯曲变形和沟道应力变化行为，这是该现象的主要原因。因此，得出结论：突出栅极结构引起的弯曲效应程度是决定Si1-xGe(x)器件沟道趋势和应力大小的关键。
