Browsing by Author "Lan, WT"

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Improved reliability of HfO2/SiON gate stack by fluorine incorporation
(2006-04-01)
Lu, WT
;
Chiein, CH
;
Lan, WT
;
Lee, TC
;
Lehnen, P
Effects of fluorine (F) incorporation on the reliabilities of pMOSFETs with HfO2/SiON gate stacks have been studied. In this letter, fluorine was incorporated during the source/drain implant step and was diffused into the gate stacks during subsequent dopant activation. The authors found that F introduction only negligibly affects the fundamental electrical properties of the transistors, such as threshold voltage V-th, subthreshold swing, gate leakage current, and equivalent oxide thickness. In contrast, reduced generation rates in interface states and charge trapping under constant voltage stress and bias temperature stress were observed for the fluorine-incorporated split. Moreover, the authors demonstrated for the first time that F incorporation could strengthen the immunity against plasma charging damage.
Improvements on electrical characteristics of p-channel metal-oxide-semiconductor field effect transistors with HfO(2) gate stacks by post deposition N(2)O plasma treatment
(2005-11-01)
Lu, WT
;
Chien, CH
;
Lan, WT
;
Lee, TC
;
Yang, MJ
In this work, we found that employing a post deposition N(2)O plasma treatment following the deposition of HfO(2) film can effectively improve the electrical characteristics of p-type channel metal-oxide-semiconductor field-effect transistors (pMOSFETs) with a HfO(2) gate stack in terms of lower gate leakage current, lower interface state density, superior subthreshold swing, higher normalized transconductance and enhanced driving current even though it had led to a slightly higher equivalent oxide thickness (EOT) value of the HfO(2) gate stack by around 0.3 nm. In order to clarify the attributes of the improvements, we used charge pumping (CP) measurement to analyze the densities of interface states and bulk traps in the HfO(2) gate stacks. The improvements are then ascribed to the higher interface quality offered by the post deposition N(2)O plasma treatment. Moreover, we found that to more accurately estimate the bulk traps from the CP measurement, the leakage should be taken into account especially at low frequencies. Finally, it was found that the levels of the bulk traps and interface states can be reduced by the N(2)O plasma treatment, which also helps significantly eliminate the degradation of the gate stack during the subsequent voltage stress.
Improvements on electrical characteristics of p-channel metal-oxide-semiconductor field effect transistors with HfO2 gate stacks by post deposition N2O plasma treatment
(2005-11-01)
Lu, WT
;
Chien, CH
;
Lan, WT
;
Lee, TC
;
Yang, MJ
In this work, we found that employing a post deposition N2O plasma treatment following the deposition of HfO2 film can effectively improve the electrical characteristics of p-type channel metal-oxide-semiconductor field-effect transistors (pMOSFETs) with a HfO2 gate stack in terms of lower gate leakage current, lower interface state density, superior subthreshold swing, higher normalized transconductance and enhanced driving current even though it had led to a slightly higher equivalent oxide thickness (EOT) value of the HfO2 gate stack by around 0.3 nm. In order to clarify the attributes of the improvements, we used charge pumping (CP) measurement to analyze the densities of interface states and bulk traps in the HfO2 gate stacks. The improvements are then ascribed to the higher interface quality offered by the post deposition N2O plasma treatment. Moreover, we found that to more accurately estimate the bulk traps from the CP measurement, the leakage should be taken into account especially at low frequencies. Finally, it was found that the levels of the bulk traps and interface states can be reduced by the N2O plasma treatment, which also helps significantly eliminate the degradation of the gate stack during the subsequent voltage stress.