As semiconductor device sizes continue to decrease, the traditional bulk CMOS technology is seen as an obstacle itself by the physical device limitations. One of the physical limitations of MOSFETs is to ensure that the SCEs and related issues can be controlled to maintain device performance targets. For SOI MOSFETs, due to the presence of BOX, short-channel behavior is improved, as compared to bulk Si. But self-heating plays a key role in affecting device reliability. Thus, these challenges make the future of planar technology being difficult to be continuously implemented.
In this thesis we introduce the concept of the isolation-last process which moves the ¡§FET active region definition¡¨ to the back of the S/D activation process. There are two kinds of devices to be fabricated: BOSDT-APSB MOSFET and ZBOSDT-APSB MOSFET. BOSDT is the acronym of block-oxide S/D-tie and APSB is the acronym of additional poly-Si body. It should be noted that the ZBO is the acronym of zero BO (absence of BO). Actually, the two above-mentioned devices can be referred to as the poly-Si TFTs, due to the presence of poly-Si active region. However, for the ultimate scaling, the two proposed devices can have an additional silicon body or ASB. Two proposed devices, being a consideration of fabrication aspects, have a different design compared to their scaled-down sizes. But we can still hold the ASB¡¦s core values.
According to the simulation, the ASB shows its ability to alleviate the SCEs and offers improved cooling capability, which is because the additional body provides extra space for heat dissipation. The unwanted results are that the large gate leakage current and parasitic capacitances are observed as the ASB is created. Fortunately, these results are still within acceptable limits. Experimental results show that the APSB is desirable to suppress the SCEs in both BOSDT and ZBOSDT MOSFETs. We also verify that the device¡¦s cooling capability can be improved by introducing an APSB into MOSFETs. In other words, the APSB is useful for enhanced performance and reliability, although some disadvantages exist also. The BO has been proven to have a better channel controllability than its counterpart. But the ZBO can be seen as the ultimately scaled BO. And after scaling, the schemes of ZBO and ASB become more pronounced.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0725112-105314 |
| Date | 25 July 2012 |
| Creators | Eng, Yi-Chuen |
| Contributors | Pei-Wen Li, Ting-Chang Chang, Jyi-Tsong Lin, James B. Kuo, Cheewee Liu, Wei-Chou Hsu, Yao-Tsung Tsai, Chun-Hsing Shih, Feng-Der Albert Chin |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0725112-105314 |
| Rights | user_define, Copyright information available at source archive |
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