The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Albert Chin - One of the best experts on this subject based on the ideXlab platform.
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metal gate high kappa Ge nmos at small cet with higher mobility than hbox sio _ 2 hbox si at wide ranGe carrier densities
IEEE Electron Device Letters, 2013Co-Authors: Chiachun Liao, Minchen Lin, Lang Zeng, Jinfeng Kang, Xiaoyan Liu, Albert ChinAbstract:High-performance TaN/TiLaO/La2O3/SiO2/ (111)-Ge nMOSFETs show high mobility of 432 cm2/V ·s at 1013 cm-2 carrier density (Ns), good 1.05 junction ideality factor, and small subthreshold swing of 101 mV/dec, at a small 1.1-nm capacitance-equivalent thickness (CET). This is the first report of higher mobility in the Ge nMOSFET than SiO2/Si universal mobility at wide medium-high Ns ranGe and small CET of 1.1 nm, which is attributed to using the (111)-Ge Substrate, 30-ns laser annealing, SiO2 interfacial layer, and YbGex/n-Ge contact.
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effect of surface nh3 anneal on the physical and electrical properties of hfo2 films on Ge Substrate
Applied Physics Letters, 2004Co-Authors: Qingchun Zhang, D L Kwong, Albert Chin, Chunxiang Zhu, Chia Chin Yeo, S J Whang, D S H Chan, Byung Jin Cho, C H Tung, N BalasubramanianAbstract:Metal-oxide-semiconductor capacitors were fabricated on Germanium Substrates by using metalorganic-chemical-vapor-deposited HfO2 as the dielectric and TaN as the metal gate electrode. It is demonstrated that a surface annealing step in NH3 ambient before the HfO2 deposition could result in significant improvement in both gate leakaGe current and the equivalent oxide thickness (EOT). It was possible to achieve a capacitor with an EOT of 10.5 A and a leakaGe current of 5.02×10−5 A/cm2 at 1 V gate bias. X-ray photoelectron spectroscopy analysis indicates the formation of GeON during surface NH3 anneal. The presence of Ge was also detected within the HfO2 films. This may be due to Ge diffusion at the high temperature (∼400 °C) used in the chemical-vapor deposition process.
Qian Gong - One of the best experts on this subject based on the ideXlab platform.
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submonolayer quantum dot quantum cascade long wave infrared photodetector grown on Ge Substrate
Applied Physics Letters, 2021Co-Authors: Chunfang Cao, Qian Gong, Zhijian Shen, Zhuo Deng, Xuyi Zhao, Jian Huang, Xinbo Zou, Fengyu Liu, Baile ChenAbstract:A Germanium (Ge) or Germanium-on-silicon (Ge-on-Si) Substrate is an attractive yet not well-studied platform for developing long-wave infrared photonics devices such as lasers and photodetectors. In this paper, we report a long-wave infrared quantum cascade photodetector grown on the Ge Substrate with a submonolayer InAs/GaAs quantum dot as the infrared absorber. At 77 K under zero bias, the detector shows a differential-resistance area ( R 0 A) product of 298.7 Ω·cm2. The normal-incident peak responsivity is 0.56 mA/W observed at 8.3 μm, corresponding to a Johnson noise limited detectivity of 1.5 × 108 cm·Hz1/2/W. In addition, the effect of the periodic staGe number of active regions on device's performance is discussed in detail. The device characteristics presented in this work demonstrate the potential for monolithic integration of this quantum cascade detector with the Ge or Ge-on-Si Substrate for larGe-scale, cost-effective sensing and imaging applications.
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relative intensity noise of inas quantum dot lasers epitaxially grown on Ge
Optics Express, 2017Co-Authors: Yue-guang Zhou, Cheng Zhou, Chunfang Cao, Qian Gong, Cheng WangAbstract:We report the relative intensity noise (RIN) characteristics of an InAs quantum dot (Qdot) laser epitaxially grown on the Ge Substrate. It is found that the minimum RIN of the Ge-based Qdot laser is around −120 dB/Hz, which is 15 dB higher than that of a native GaAs-based Qdot laser with the same layer structure. The higher RIN in the Ge-based laser can be attributed to the high-density epitaxial defects of threading dislocations and antiphase domain boundaries.
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heteroepitaxy growth of gaasbi on Ge 100 Substrate by gas source molecular beam epitaxy
Applied Physics Express, 2016Co-Authors: Peng Wang, Chunfang Cao, Wenwu Pan, Shumin Wang, Qian GongAbstract:We have investigated the growth of GaAsBi single-crystal film on Ge Substrate by gas source molecular beam epitaxy. A high-quality GaAsBi epilayer has been obtained. It has been found that the surfactant effect of Bi suppresses the interdiffusion of Ge at the GaAsBi/Ge interface and reduces the misfit dislocation density. The Bi atoms occupy the As sites, as indicated by the appearance of GaBi-like TO(G) and LO(G) phonon modes in Raman spectra. In addition, the redshift of the GaAs-like LO(G) phonon frequency has been observed in the Raman spectra, owing to the Bi-induced biaxial strain and the alloying effect as well.
Zhijian Shen - One of the best experts on this subject based on the ideXlab platform.
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submonolayer quantum dot quantum cascade long wave infrared photodetector grown on Ge Substrate
Applied Physics Letters, 2021Co-Authors: Chunfang Cao, Qian Gong, Zhijian Shen, Zhuo Deng, Xuyi Zhao, Jian Huang, Xinbo Zou, Fengyu Liu, Baile ChenAbstract:A Germanium (Ge) or Germanium-on-silicon (Ge-on-Si) Substrate is an attractive yet not well-studied platform for developing long-wave infrared photonics devices such as lasers and photodetectors. In this paper, we report a long-wave infrared quantum cascade photodetector grown on the Ge Substrate with a submonolayer InAs/GaAs quantum dot as the infrared absorber. At 77 K under zero bias, the detector shows a differential-resistance area ( R 0 A) product of 298.7 Ω·cm2. The normal-incident peak responsivity is 0.56 mA/W observed at 8.3 μm, corresponding to a Johnson noise limited detectivity of 1.5 × 108 cm·Hz1/2/W. In addition, the effect of the periodic staGe number of active regions on device's performance is discussed in detail. The device characteristics presented in this work demonstrate the potential for monolithic integration of this quantum cascade detector with the Ge or Ge-on-Si Substrate for larGe-scale, cost-effective sensing and imaging applications.
W Stolz - One of the best experts on this subject based on the ideXlab platform.
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a gaas metalorganic vapor phase epitaxy growth process to reduce Ge outdiffusion from the Ge Substrate
Applied Physics Letters, 2008Co-Authors: B Galiana, Ignacio Reystolle, C Algora, K Volz, W StolzAbstract:A barrier based on GaAs for controlling the Ge out diffusion has been developed by metalorganic vapor phase epitaxy. It is based on a thin GaAs layer (50nm) grown at a low temperature (≈500°C) on top of a predeposition layer, showing that GaAs prevents the Ge diffusing when it is grown at a low temperature. Additionally, two different predeposition monolayers have been compared, concluding that when the Ga is deposited first, the diffusions across the GaAs∕Ge heterointerface decrease.
Shigeaki Zaima - One of the best experts on this subject based on the ideXlab platform.
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non uniform depth distributions of sn concentration induced by sn migration and desorption during Gesnsi layer formation
Applied Physics Letters, 2015Co-Authors: Noriyuki Taoka, Takanori Asano, Takashi Yamaha, Tatsuya Terashima, Osamu Nakatsuka, Ioan Costina, P Zaumseil, Giovanni Capellini, Shigeaki Zaima, Thomas SchroederAbstract:The distributions of Sn concentration in GeSnSi layers formed on Ge Substrate at various temperatures were investigated. High deposition temperature (Td) induces significant Sn migration and desorption, which have activation energies of 0.75 eV and 0.27 eV, respectively. A model quantitatively clarified the Sn migration fluxes during the deposition, which increase not only with increasing Td but also with the layer thickness. A non-negligible Sn flux compared with the supplied flux was found at 350 °C at the surface of the 200-nm-thick layer. Consequently, designs of layer thickness and Td taking into account the appropriate Sn flux are important to form a GeSnSi layer with uniform Sn content for future optoelectronics.
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effect of interfacial reactions in radical process on electrical properties of al2o3 Ge gate stack structure
Journal of Physics: Conference Series, 2013Co-Authors: Osamu Nakatsuka, Kimihiko Kato, Mitsuo Sakashita, Wakana Takeuchi, Shigeaki ZaimaAbstract:We have investigated the interfacial reactions of Al2O3/Ge structure with nitroGen (N) radical process, and the effect of the chemical bonding states on electrical properties. The angle resolved hard X-ray photoelectron spectroscopy measurement revealed that oxyGen is supplied from the Al2O3 film to the interface with Ge Substrate during N radical process and Ge atoms diffuse into the Al2O3 film. As a result, AlGeON/Ge suboxide/Ge stacked structure is formed by N radical process. From capacitance-voltaGe characteristics of Al/AlGeON/Ge suboxide/Ge MOS capacitors, both the interface state density at the interface and the carrier trap density in the Al2O3 film are effectively decreased by the formation of AlGeON/Ge suboxide/Ge structure. The interface state density decreases with increasing in the thickness of Ge suboxide at the interface.
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low temperature growth of Ge1 xsnx buffer layers for tensile strained Ge layers
Thin Solid Films, 2010Co-Authors: Yosuke Shimura, Osamu Nakatsuka, Norimasa Tsutsui, Akira Sakai, Shigeaki ZaimaAbstract:Abstract We have investigated the dependence of Sn precipitation and crystallinity of Ge1 − xSnx layers on the growth temperature. We also demonstrated a growth of a tensile–strained Ge layer on strain-relaxed Ge1 − xSnx buffer layers. In order to suppress Sn precipitation in Ge1 − xSnx layers and improve the crystalline quality, we strongly sugGest that point defects have to be introduced by using low temperature growth MBE. The point defects effectively contribute to the lateral propagation of misfit dislocations at the Ge1 − xSnx/virtual Ge Substrate. The point defects would be also effective to stabilize substitutional Sn atoms in Ge1 − xSnx layers due to the formation of Sn-vacancy pairs. As a result, Sn precipitation was suppressed in the Ge1 − xSnx layer by low temperature growth, and we realized the Ge1 − xSnx layer with a Sn content of 7.1%. We also achieved the formation of the Ge layer with a tensile–strain value of 0.71%.
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control of sn precipitation and strain relaxation in compositionally step graded Ge1 xsnx buffer layers for tensile strained Ge layers
Japanese Journal of Applied Physics, 2009Co-Authors: Yosuke Shimura, Osamu Nakatsuka, Norimasa Tsutsui, Akira Sakai, Shigeaki ZaimaAbstract:We investigated the relationship between Sn precipitation and strain relaxation in Ge1-xSnx buffer layers grown by the compositionally step-graded (CSG) method on a virtual Ge Substrate. We found that the strain in the upper Ge1-xSnx layers is reduced by Sn precipitation rather than the lateral propagation of misfit dislocations at the interfaces of upper Ge1-xSnx layers in the CSG method. The critical misfit strain was increased to 5.8 ×10-3 compared with that in our previous work by lowering the temperature of the postdeposition annealing, and a Sn content of 6.3% in the Ge1-xSnx buffer layer was achieved with a larGe degree of strain relaxation using only two stacked layers of the CSG structure. An in-plane tensile strain of 0.62% in a 30-nm-thick Ge layer fabricated on these Ge1-xSnx buffer layers was achieved.
