Bo Chin Wang

Comparison of the trap behavior between ZrO 2 and HfO 2 gate stack nMOSFETs by 1/f noise and random telegraph noise

Low-frequency (1/<i>f</i>) noise characteristics of 28-nm nMOSFETs with ZrO₂/SiO₂ and HfO₂/SiO₂ dielectric gate stacks have been investigated. The observed lower 1/<i>f</i> noise level in ZrO₂ devices, as compared with that in HfO₂ devices, is attributed to the reduction in tunneling attenuation length and in trap density simultaneously. Experimental results showed that the trap behavior of ZrO₂/SiO₂ dielectric gate stack changes not only the trap location from a high-<i>k</i> layer to a SiO₂ interfacial layer but also the noise-dominated mechanism from carrier number fluctuation to the unified fluctuation model, which includes number fluctuation and correlated mobility fluctuation.

Correlation Between Random Telegraph Noise and

The random telegraph noise (RTN) characteristics of 28-nm pMOSFETs with tip-shaped SiGe source/drain have been investigated. RTN analysis found that strained devices undergo higher compressive strain; the trap position from the Si/SiO2 interface is reduced, because of the closer trap energy level near the valence band. Although tip-shaped SiGe process induces higher oxide trap density, the trap position corresponding to the tunneling attenuation length (λ) may result in lower 1/f noise level in tip-shaped SiGe S/D devices as compared with that of control devices.

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We have studied the low-frequency noise characterizations in 28-nm high-k (HK) pMOSFET with embedded SiGe source/drain (S/D) through noise and random telegraph noise measurements simultaneously. It is found that uniaxial compressive strain really existed in HK pMOSFET with embedded SiGe S/D. The compressive strain induced the decrease in the tunneling attenuation length reflecting in the oxide trap depth from Si/SiO2 interface to the HK layer, so that the oxide traps at a distance from insulator/semiconductor interface cannot capture carrier in the channel. Consequently, lower noise level in HK pMOSFET with embedded SiGe S/D is observed, thanks to the less carrier fluctuations from trapping/detrapping behaviors. This result represents an intrinsic benefit of HK pMOSFET using embedded SiGe S/D in low-frequency noise characteristics.

Noise Parameters in 28-nm pMOSFETs With Tip-Shaped SiGe Source/Drain

The growth of vertically aligned cobalt-doped ZnO (Co-ZnO) nanorods on a glass substrate using a low-temperature hydrothermal method is reported. A Co-ZnO nanorod metal-semiconductor-metal ultraviolet photodetector (PD) was also fabricated. The ratio of UV-to-visible rejection of the fabricated PD was approximately 11700 when biased at 1 V with a sharp cutoff at 380 nm. With an incident light wavelength of 380 nm and an applied bias of 1 V, the measured responsivity of the PD was found to be 19.8 A/W. Furthermore, the dark noise equivalent power (NEP) and photo NEP of the fabricated Co-ZnO nanorod MSM PD were 1.3 × 10^-13 and 1.8 × 10^-11 W at the corresponding dark detectivities (D*) and photo D* of 1.1 × 10¹⁴ and 7.3 × 10¹¹ cm · Hz ^0.5 · W ^-1, respectively.

Investigation of Low-Frequency Noise Characterization of 28-nm High-k pMOSFET with Embedded SiGe Source/Drain

In this letter, the effect of adding ZrO2 to different positions in an HfO2-based high-k (HK) gate-stack is investigated by a low-frequency (1/ f ) noise measurement. The tested nMOSFETs are fabricated using 28-nm gate-last HK/metal-gate technology with a ~ 1-nm SiO2 interfacial layer. The 1/f noise mechanism of these devices is described by the carrier number fluctuation, and the extracted trap densities (Nt)are 8.9 × 1018-5.1 × 1019 eV-1 cm-3. However, reference devices with a pure ZrO2 gate dielectric exhibit 1/f noise characteristics that are consistent with the unified model, which incorporates both the carrier number and the correlated mobility fluctuations. The reference devices are with lower Nt values in the range of 5.8 × 1017-2.4 × 1018 eV-1 cm-3. In addition, there is an increase in Nt as the initial HfO2 layer becomes thicker.These results show that the trapping behavior is mainly dominated by the HfO2 film and is dependent on the thickness of the initial HfO2 layer in the ZrO2/HfO2/SiO2gate-stack.

Noise Properties of Low-Temperature-Grown Co-Doped ZnO Nanorods as Ultraviolet Photodetectors

In this study, the trap properties of composite Hf0.83Zr0.17O2 high-k gate stack p-type MOSFETs (pMOSFETs) were investigated by simultaneous low-frequency (1/f) noise and random telegraph noise measurements. Compared with pure ZrO2 pMOSFETs, the interface property and drive current of Hf0.83Zr0.17O2 pMOSFETs were both improved, and the depth of the effective centroid of the fixed charges was close to the insulator/semiconductor interface. This result indicated that the trapping behavior of hole capture from a ZrO2 film can be suppressed by mixing the film with a HfO2 film. Consequently, comparable oxide trap densities and trapping depths between Hf0.83Zr0.17O2 and HfO2 pMOSFETs can be seen. In addition, it was found that the unified model can appropriately interpret the 1/f noise mechanism in Hf0.83Zr0.17O2 pMOSFETs.

Low-frequency noise characteristics for various ZrO2-added HfO2-based 28-nm High-k/metal-gate nMOSFETs

In this study, the impact of embedded tip-shaped SiGe in the source/drain (S/D) region on individual trap behavior such as activation energy and depth from the SiO2/Si interface of the 28 nm p-type metal–oxide–semiconductor field-effect transistors (pMOSFETs) has been investigated on the basis of drain current random telegraph noise (RTN). The purpose of implementing tip-shaped SiGe S/D is to further increase channel stress because it provides a closer proximity of embedded SiGe to the channel. By characterizing RTN, we found that the pMOSFETs underwent uniaxial compressive strain that was provided by tip-shaped SiGe S/D, and the trap energy level being close to the channel valence band resulted in the trap located close to the Si/SiO2 interface, as compared with the control device without embedded SiGe S/D.

Investigation of trap properties of Hf0.83Zr0.17O2 high-k gate stack p-type MOSFETs by low-frequency (1/f) noise and random telegraph noise analyses

In this letter, the effect of adding ZrO2 to different positions in an HfO2-based high-k (HK) gate-stack is investigated by a low-frequency (1/ f ) noise measurement. The tested nMOSFETs are fabricated using 28-nm gate-last HK/metal-gate technology with a ~ 1-nm SiO2 interfacial layer. The 1/f noise mechanism of these devices is described by the carrier number fluctuation, and the extracted trap densities (Nt)are 8.9 × 1018-5.1 × 1019 eV-1 cm-3. However, reference devices with a pure ZrO2 gate dielectric exhibit 1/f noise characteristics that are consistent with the unified model, which incorporates both the carrier number and the correlated mobility fluctuations. The reference devices are with lower Nt values in the range of 5.8 × 1017-2.4 × 1018 eV-1 cm-3. In addition, there is an increase in Nt as the initial HfO2 layer becomes thicker.These results show that the trapping behavior is mainly dominated by the HfO2 film and is dependent on the thickness of the initial HfO2 layer in the ZrO2/HfO2/SiO2gate-stack.

Characterization of Oxide Tarps in 28 nm p-Type Metal--Oxide--Semiconductor Field-Effect Transistors with Tip-Shaped SiGe Source/Drain Based on Random Telegraph Noise

HfO2 and ZrO2 nMOSFETs San Lein Wu, Bo Chin Wang, Yu Ying Lu, Shih Chang Tsai, Jone Fang Chen, Shoou Jinn Chang, Sheng Po Chang, Che Hua Hsu, Chih Wei Yang, Cheng Guo Chen, Osbert Cheng, and Po Chin Huang 1 Department of Electronic Engineering, Cheng Shiu University, Kaohsiung City 833, Taiwan 2 Institute of Microelectronics and Department of Electrical Engineering, National Cheng Kung University, Tainan City 701, Taiwan 3 Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan City 701, Taiwan 4 Central R&D Division, United Microelectronics Corp., Tainan City 744, Taiwan Phone: +886-6-2757575 ext.62400-1223 Fax: +886-6-2761854 e-mail: pchuang@mail.ncku.edu.tw

Low-Frequency Noise Characteristics for Various -Added -Based 28-nm High- /Metal-Gate nMOSFETs

In this letter, the effect of adding ZrO2 to different positions in an HfO2-based high-k (HK) gate-stack is investigated by a low-frequency (1/ f ) noise measurement. The tested nMOSFETs are fabricated using 28-nm gate-last HK/metal-gate technology with a ~ 1-nm SiO2 interfacial layer. The 1/f noise mechanism of these devices is described by the carrier number fluctuation, and the extracted trap densities (Nt)are 8.9 × 1018-5.1 × 1019 eV-1 cm-3. However, reference devices with a pure ZrO2 gate dielectric exhibit 1/f noise characteristics that are consistent with the unified model, which incorporates both the carrier number and the correlated mobility fluctuations. The reference devices are with lower Nt values in the range of 5.8 × 1017-2.4 × 1018 eV-1 cm-3. In addition, there is an increase in Nt as the initial HfO2 layer becomes thicker.These results show that the trapping behavior is mainly dominated by the HfO2 film and is dependent on the thickness of the initial HfO2 layer in the ZrO2/HfO2/SiO2gate-stack.