Ultrathin-body strained-Si and SiGe heterostructure-on-insulator MOSFETs
Ultrathin-body strained-Si and SiGe heterostructure-on-insulator MOSFETs
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DOI：
10.1109/ted.2006.871847
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发表时间：
2006-04
影响因子：
3.1
通讯作者：
I. Åberg;Cait Ni Chleirigh;J. Hoyt
中科院分区：
文献类型：
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作者：
I. Åberg;Cait Ni Chleirigh;J. Hoyt
应变工程等沟道迁移率增强技术与超薄体（UTB）或双栅结构等非经典MOS器件架构相结合，有望在保持未来技术节点中积极器件缩放所需的静电控制的同时，最大限度地提高电流驱动。实验比较了两种材料的UTBMOSFET在输运增强和关态漏电流之间的折衷：1）直接在绝缘体上的应变Si（SSDOI）和2）应变Si/应变Si/sub 1-z/Ge/sub z/（z=0.46-0.55）/应变Si/heterostructure-on-insulator（HOI）。中等应变水平（例如/spl sim/ 0.8%）的SSDOI对于所有电子密度产生高电子迁移率增强，而需要高应变水平（例如/spl sim/ 1.6%）以在高反转电荷密度下获得空穴迁移率增强。HOI被证明具有类似的电子迁移率特性SSDOI，而空穴迁移率得到改善，并可以保持在高的反转电荷密度。研究了厚度小于10 nm的应变沟道中的空穴迁移率，并对SSDOI和HOI进行了比较。随着沟道厚度的减小，迁移率降低，如在无应变绝缘体上硅（SOI），虽然空穴迁移率增强被证明到超薄沟道制度。与SSDOI和SOI相比，在HOI中观察到增加的关态漏电流。对于4 nm厚的掩埋SiGe层，相对于具有较厚SiGe沟道的器件，泄漏减少。
The combination of channel mobility-enhancement techniques such as strain engineering with nonclassical MOS device architectures, such as ultrathin-body (UTB) or double-gate structures, offers the promise of maximizing current drive while maintaining the electrostatic control required for aggressive device scaling in future technology nodes. The tradeoff between transport enhancement and OFF-state leakage current is compared experimentally for UTB MOSFETs in two types of materials: 1) strained Si directly on insulator (SSDOI) and 2) strained Si/strained Si/sub 1-z/Ge/sub z/ (z=0.46-0.55)/strained Si heterostructure-on-insulator (HOI). SSDOI of moderate strain level (e.g. /spl sim/ 0.8%) yields high electron-mobility enhancements for all electron densities, while high strain levels (e.g. /spl sim/ 1.6%) are required to obtain hole-mobility enhancements at high inversion charge densities. HOI is demonstrated to have similar electron-mobility characteristics to SSDOI, while hole mobilities are improved and can be maintained at high inversion charge densities. Hole mobility in strained channels with thickness below 10 nm is studied and compared for SSDOI and HOI. As the channel thickness is reduced, mobility decreases, as in unstrained silicon-on-insulator (SOI), though hole-mobility enhancements are demonstrated into the ultrathin-channel regime. Increased OFF-state leakage currents are observed in HOI compared to SSDOI and SOI. For a 4-nm-thick buried SiGe layer, leakage is reduced relative to devices with thicker SiGe channels.