Early-Voltage Variation and Dependence of VT Implant for n-type FinFETs

• Main Authors: WANG,YU-WEI, 王昱崴
• Other Authors: WANG,MU-CHUN
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/47365866755668715959

碩士 === 明新科技大學 === 電子工程系碩士班 === 104 === Planar field effect transistors in semiconductor industry have been used for a long time, playing a main role in the past. Since the process technology is promoted, the shrinkage of device profile is well done. However, this technology gradually approaches the physical limitation. Most of researchers or scientists seek the other available alternatives. A fin field effect transistor (FinFET) device seems a good choice in this process era. In this study, the FinFETs compared to the conventional planar field-effect transistors, increasing the transistor channel width (Wfin + 2Hfin), which is to make the drive current. This transistor device is formed on the Unibond SOI wafer structure, a channel thickness of about 80 nm deposited as Si crystalline layer. Using the hard mask, the Si-fin can be fabricated. To improve the drive current, FinFETs possibly offer the multi-channel scheme instead of the single-channel device. In this experiment, the channel-length modulation (CLM) is applied to explore the Early voltage (VA) in a FinFET device, which the L/L change is caused from the horizontal and vertical field of dependency in channel. Furthermore, the VA values for single or multi-channel FinFETs are related to the device profile, the temperature stress, and the VT implant energy. These relationships will also be investigated. Due to these efforts, the suitable device models will be provided to the IC design customers. In this measurement test, there is more influence to the VA as the tested device is single-channel mode operated at the lower electrical field (VGS-VT). For multi-channel tested devices, the VA is impacted obviously at the middle field or higher. As the stress temperature is increased, the channel lengths are different, or the VT implant energies are not the same, the VA is indeed influenced. However, the trend is not easy to be classified well. The speculation is possibly when the device profile is shrunk, the uniformity of VT implant is not optimally approached to cause the channel electrical field is not easy to be controlled well.