Browsing by Author "Chang, Sou-Chi"

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Temperature-Dependent Remote-Coulomb-Limited Electron Mobility in n(+)-Polysilicon Ultrathin Gate Oxide nMOSFETs
(2011-04-01)
Chen, Ming-Jer
;
Chang, Sou-Chi
;
Kuang, Shin-Jiun
;
Lee, Chien-Chih
;
Lee, Wei-Han
Additional electron mobility due to remote scatterers in n(+)-polysilicon 1.65-nm gate oxide (SiO(2)) n-channel metal-oxide-semiconductor field-effect transistors is experimentally extracted at three different temperatures (i.e., 233, 263, and 298 K). The core of the extraction process consists of simulated temperature-dependent universal mobility curves and Matthiessen's rule in a mobility universality region. Resulting additional mobility for the first time experimentally exhibits a negative temperature coefficient, confirming interface plasmons in a polysilicon depletion region to be dominant remote Coulomb scatterers. We also present corroborative evidence as quoted in the literature, including: 1) calculated temperature-dependent remote Coulomb mobility due to ionized impurity atoms in a polysilicon depletion region; 2) experimentally assessed additional mobility at room temperature; and 3) simulated remote Coulomb mobility due to interface plasmons in a polysilicon depletion region as well as its temperature coefficient. Validity of Matthiessen's rule used in this paper is verified.
Temperature-Oriented Mobility Measurement and Simulation to Assess Surface Roughness in Ultrathin-Gate-Oxide (similar to 1 nm) nMOSFETs and Its TEM Evidence
(2012-04-01)
Chen, Ming-Jer
;
Chang, Li-Ming
;
Kuang, Shin-Jiun
;
Lee, Chih-Wei
;
Hsieh, Shang-Hsun
On a 1.27-nm gate-oxide nMOSFET, we make a comprehensive study of SiO2/Si interface roughness by combining temperature-dependent electron mobility measurement, sophisticated mobility simulation, and high-resolution transmission electron microscopy (TEM) measurement. Mobility measurement and simulation adequately extract the correlation length lambda and roughness rms height Delta of the sample, taking into account the Coulomb-drag-limited mobilities in the literature. The TEM measurement yields the apparent correlation length lambda(m) and roughness rms height Delta(m). It is found that the following hold: 1) lambda approximate to lambda(m) for both the Gaussian and exponential models, validating the temperature-oriented extraction process; 2) the extracted Delta (similar to 1.3 angstrom for the Gaussian model and 1.0 angstrom for the exponential one) is close to that (similar to 1.2 angstrom) of Delta(m), all far less than the conventional values (similar to 3 angstrom) in thick-gate-oxide case; and 3) the TEM 2-D projection correction coefficient Delta(m)/Delta is approximately 1.0, which cannot be elucidated with the current thick-gate-oxide-based knowledge.