Browsing by Author "Zhu, CX"

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A high-density MIM capacitor (13 fF/mu m(2)) using ALD HfO2 dielectrics
(2003-02-01)
Yu, XF
;
Zhu, CX
;
Hu, H
;
Chin, A
;
Li, MF
Metal-insulator-metal (MIM) capacitors with a different thickness of HfO2 have been investigated. The results show that both the capacitance density and voltage coefficients of capacitance (VCCs) increase with decreasing the HfO2 thickness. In addition, it is also found that the VCCs decrease logarithmically with increasing the thickness Of HfO2. Furthermore, the MIM capacitor with 10-nm HfO2 shows a record high capacitance density of 13 fF/mum(2) and a VCC of 607 ppm/V, which can meet the requirement of the International Technology Roadmap for Semiconductors. It can also provide a low leakage current of 5.95 x 10-(8)A/cm(2) at room temperature at I V, low tangent values below 0.05, and a small frequency dependence as well. All these indicate that it is very suitable for use in silicon integrated circuit applications.
A novel program-erasable high-(K) A1N-Si MIS capacitor
(2005-03-01)
Lai, CH
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Chin, A
;
Hung, BF
;
Cheng, CF
;
Yoo, WJ
We demonstrate a programmable-erasable MIS capacitor with a single layer high-kappa AIN dielectric on Si having a high capacitance density of 5 fF/mum(2). It has low program and erase voltages of +4 and -4 V, respectively. Such an erase function is not available in other single layer Al2O3, AION, or other known high-kappa dielectric capacitors, where the threshold voltage (T h) shifts continuously with voltage. This device exhibits good data retention with a V-th change of only 0.06 V after 10 000 s.
A TaN-HfO2-Ge pMOSFET with novel SiH4 surface passivation
(2004-09-01)
Wu, N
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Zhang, QC
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Zhu, CX
;
Chan, DSH
;
Du, AY
In this letter, we demonstrate a novel surface passivation process for HfO2 Ge pMOSFETs using SiH4 surface annealing prior to HfO2 deposition. By using SiH4 passivation, a uniform amorphous interfacial layer is formed after device fabrication. Electrical results show that the HfO2 Ge MOSFET with Si-passivation exhibits less frequency dispersion, narrower gate leakage current distribution, and a similar to 140% higher peak mobility than that of the device with surface nitridation.
Al2O3-Ge-On-insulator n- and p-MOSFETs with fully NiSi and NiGe dual gates
(2004-03-01)
Yu, DS
;
Huang, CH
;
Chin, A
;
Zhu, CX
;
Li, MF
High-kappa, A1(2)O(3)/Ge-on-insulator (GOI) n- and p-MOSFETs with fully silicided NiSi and germanided NiGe dual gates were fabricated. At 1.7-nm equivalent-oxide-thickness (EOT), the A1(2)O(3)-GOI with metal-like NiSi and NiGe gates has comparable gate leakage current with A1(2)O(3)-Si MOSFETs. Additionally, A1(2) O-3-GOI C-MOSFETs with fully NiSi and NiGe gates show 1.94 and 1.98 times higher electron and hole mobility, respectively, than A1(2)O(3)-Si devices, because the electron and hole effective masses of Ge are lower than those of Si. The process with maximum 500 degreesC rapid thermal annealing (RTA) is ideal for integrating metallic gates with high-kappa to minimize interfacial reactions and crystallization of the high-kappa material, and oxygen penetration in high-kappa MOSFETs.
Alternative surface passivation on germanium for metal-oxide-semiconductor applications with high-k gate dielectric
(2004-11-01)
Wu, N
;
Zhang, QC
;
Zhu, CX
;
Chan, DSH
;
Li, MF
An alternative surface passivation process for high-k Ge metal-oxide-semiconductor (MOS) device has been studied. The surface SiH4 annealing was implemented prior to HfO2 deposition. X-ray photoelectron spectroscopy analysis results show that the SiH4 surface passivation can greatly prevent the formation of unstable germanium oxide at the surface and suppress the Ge out-diffusion after the HfO2 deposition. The electrical measurement shows that an equivalent oxide thickness of 13.5 Angstrom and a leakage current of 1.16x10(-5) A/cm(2) at 1 V gate bias was achieved for TaN/HfO2/Ge MOS capacitors with the SiH4 surface treatment. (C) 2004 American Institute of Physics.
Effect of surface NH3 anneal on the physical and electrical properties of HfO2 films on Ge substrate
(2004-05-10)
Wu, N
;
Zhang, QC
;
Zhu, CX
;
Yeo, CC
;
Whang, SJ
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 Angstrom and a leakage current of 5.02x10(-5) A/cm(2) 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 (similar to400 degreesC) used in the chemical-vapor deposition process. (C) 2004 American Institute of Physics.
Electrical characteristics and suppressed boron penetration behavior of thermally stable HfTaO gate dielectrics with polycrystalline-silicon gate
(2004-10-04)
Yu, XF
;
Zhu, CX
;
Li, MF
;
Chin, A
;
Du, AY
The thermal stability and electrical characteristics of HfTaO gate dielectric with polycrystalline-silicon gate have been investigated. The incorporation of Ta into HfO2 enhances the crystallization temperature of film dramatically. Transmission electron microscopy micrographs confirm that HfTaO with 43% Ta film remains amorphous even after activation annealing at 950 degreesC for 30 s, and the formation of low-kappa interfacial layer is observably reduced. The capacitance-voltage curve of metal-oxide-semiconductor capacitor using HfTaO gate dielectric fits well with simulated curve, indicating good interface property between HfTaO and substrate. In addition, the boron penetration behaviors of HfTaO films are sufficiently suppressed as manifested by the narrow flat-band voltage shift. The negligible flat-band voltage shift in HfTaO with 43% Ta film is observed and attributed to its amorphous structure after device fabrication. (C) 2004 American Institute of Physics.
Electron mobility in Ge and strained-Si channel ultrathin-body metal-oxide semi conductor field-effect transistors
(2004-09-20)
Low, T
;
Li, MF
;
Shen, C
;
Yeo, YC
;
Hou, YT
Electron mobility in strained silicon and various surface oriented germanium ultrathin-body (UTB) metal-oxide semiconductor field-effect transistors (MOSFETs) with sub-10-nm-body thickness are systematically studied. For biaxial tensile strained-Si UTB MOSFETs, strain effects offer mobility enhancement down to a body thickness of 3 nm, below which strong quantum confinement effect renders further valley splitting via application of strain redundant. For Ge channel UTB MOSFETs, electron mobility is found to be highly dependent on surface orientation. Ge<100> and Ge<110> surfaces have low quantization mass that leads to a lower mobility than that of Si in aggressively scaled UTB MOSFETs. (C) 2004 American Institute of Physics.
Fully silicided NiSi and germanided NiGe dual gates on SiO2 n- and p-MOSFETs
(2003-12-01)
Yu, DS
;
Wu, CH
;
Huang, CH
;
Chin, A
;
Chen, WJ
We have fabricated the fully silicided NiSi and germanided NiGe dual gates n- and p-MOSFETs on 1.9 nm thick SiO2 gate dielectric. The extracted work functions of fully NiSi and NiGe gates from thickness-dependent flat band voltage were 4.55 and 5.2 eV respectively, which may provide possible wide work function tuning using NiSi1-xGex. In additional to the lower gate current than Al gate n- and p-MOSFETs, the fully silicided NiSi and germanided NiGe gates MOSFETs show electron and hole mobilities close to universal mobility values with special advantage of process compatible to current VLSI fabrication line.
Fully silicided NiSi and germanided NiGe dual gates on SiO2/Si and Al2O3/Ge-on-insulator MOSFETs
(2003)
Huang, CH
;
Yu, DS
;
Chin, A
;
Wu, CH
;
Chen, WJ
We demonstrate for the first time fully silicided NiSi (4.55eV) and germanided NiGe (5.2eV) dual gates on 1.9nm-SiO2/Si and Al2O3/Ge-On-Insulator (GOI) MOSFETs (EOT = 1.7nm). In additional to the comparable gate current and time-to-breakdown with AI gate C-MOSFETs, the fully NiSi and NiGe gates on SiO2/Si show mobility close to universal mobility while on Al2O3/GOI show similar to2.0X higher peak electron and hole mobility than Al on Al2O3/Si with special advantage of NiSi and NiGe compatible to current VLSI process line.
Fully silicided NiSi gate on La2O3 MOSFETs
(2003-05-01)
Lin, CY
;
Ma, MW
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Chin, A
;
Yeo, YC
;
Zhu, CX
We have fabricated the fully silicided NiSi on La2O3 for n- and p-MOSFETs. For 900 degreesC fully silicided CoSi2 on La2O3 gate dielectric with 1.5 mn EOT, the, gate dielectric has large leakage current by possible excess Co diffusion at high silicidation temperature. In sharp contrast, very low gat e leakage current density of 2 x 10(-4) A/cm(2) at 1 V is measured for 400 degreesC formed fully silicided NiSi and comparable with Al gate. The extracted work function of NiSi was 4.42 eV, and the corresponding threshold voltages are 0.12 and -0.70 V for respective n- and p-MOSFETs. Electron and hole mobilities of 156 and 44 cm(2)/V-s are obtained for respective n- and p-MOSFETs, which are comparable with the HfO2 MOSFETs without using H-2 annealing.
Germanium pMOSFETs with Schottky-barrier germanide S/D, high-kappa gate dielectric and metal gate
(2005-02-01)
Zhu, SY
;
Li, R
;
Lee, SJ
;
Li, MF
;
Du, AY
Schottky-barrier source/drain (S/D) germanium p-channel MOSFETs are demonstrated for the first time with HfAlO gate dielectric, HfN-TaN metal gate and self-aligned NiGe S/D. The drain drivability is improved over the silicon counterpart with PtSi S/D by as much as similar to5 times due to the lower hole Schottky barrier of the NiGe-Ge contact than that of PtSi-Si contact as well as the higher mobility of Ge channel than that of Si.
High density RF MIM capacitors using high-kappa AlTaOx dielectrics
(2003)
Huang, CH
;
Yang, MY
;
Chin, A
;
Zhu, CX
;
Li, MF
Very high capacitance density of 10 fF/mum(2) is measured using high-kappa AlTaOx, with small capacitance reduction of 5% from 10 KHz to 30 GHz, low loss tangent < 0.03, and process compatible with existing VLSI back-end integration. Small voltage dependence of capacitance < 600 ppm, mathematical derived from S-parameters, is obtained at 1 GHz, which ensures this MIM capacitor useful for high precision circuits operated at RF regime.
High-density MIM canpacitors using AlTaOx dielectrics
(2003-05-01)
Yang, MY
;
Huang, CH
;
Chin, A
;
Zhu, CX
;
Li, MF
The authors have obtained good MIM capacitor integrity of high-capacitance density of 10 fF/mum(2) using high-k AlTaOx fabricated at 400degreesC. In addition, small voltage dependence of capacitance of < 600, ppm (quadratic voltage coefficient of only 130 ppm/V-2). is obtained at 1 GHz using their mathematical derivation from measured high-frequency S parameters. These good results ensure the high-k AlTaOx. MIM capacitor technology is useful for high-precision circuits operated at the RF frequency regime.
High-performance MIM capacitor using ALD high-k HfO2-Al2O3 laminate dielectrics
(2003-12-01)
Ding, SJ
;
Hu, H
;
Lim, HF
;
Kim, SJ
;
Yu, XF
For the first time, we successfully fabricated and demonstrated high performance metal-insulator-metal (MIM) capacitors with HfO2-Al2O3 laminate dielectric' using atomic im layer deposition (ALD) technique. Our data indicates that the laminate NUM capacitor can provide high capacitance density of 12.8 fF/ mum(2) from 10 kHz up to 20 GHz, very low leakage current of 3.2 x 10(-8) A/cm(2) at 3.3 V, small linear voltage coefficient of capacitance of 240 ppm/V together with quadratic. one of 1830 PPM/V-2, temperature coefficient of capacitance of 182 ppm/degreesC, and high breakdown field of similar to6 MV/cm as well as promising reliability. As a result, the HfO2-Al2O3 laminate is a very promising candidate for next generation MINI capacitor for radio frequency and mixed signal integrated circuit applications.
Integrated antennas on Si with over 100 GHz performance, fabricated using an optimized proton implantation process
(2003-11-01)
Chan, KT
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Chin, A
;
Lin, YD
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Chang, CY
;
Zhu, CX
We have improved the performance of integrated antennas on Si for possible application in wireless communications and wireless interconnects. For practical VLSI integration, we have reduced the antenna size and optimized the proton implantation to a low energy of similar to 4 MeV with a depth of similar to 175 mum. To avoid any possible contamination, the ion implantation is applied after device fabrication. Excellent performance such as very low RF power loss up to 50 GHz, record high 103 GHz antenna resonance, and sharp 5 GHz bandwidth have been achieved.
Lanthanide (Tb)-doped HfO2 for high-density MIM capacitors
(2003-07-01)
Kim, SJ
;
Cho, BJ
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Li, MF
;
Zhu, CX
;
Chin, A
A high-density metal-insulator-metal (MIM) capacitor with a lanthanide-doped HfO2 dielectric prepared by physical vapor deposition (PVD) is presented for the first time. A significant improvement was shown in both the voltage coefficient of capacitance (VCC) and the leakage current density of MIM capacitor, yet the high capacitance density of HfO2 dielectrics was maintained by achieving the doping of Tb with an optimum concentration in HfO2. This technique allows utilizing thinner dielectric film in MIM capacitors and achieving a capacitance density as high as 13.3 fF/mum(2) with leakage current and VCC values that fully meet requirements from year 2005 for radio frequency (RF) bypass capacitors applications.
Low temperature MOSFET technology with Schottky barrier source/drain, high-K gate dielectric and metal gate electrode
(2004-10-01)
Zhu, SY
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Yu, HY
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Chen, JD
;
Whang, SJ
;
Chen, JH
Both P- and N-channel MOSFET's with Schottky barrier silicide source/drain (S/D), high-K gate dielectric and metal gate were successfully fabricated using a simplified low temperature process. The highest temperature after the high-K dielectric formation is 420degreesC. PMOSFETs with PtSi S/D show excellent electrical performance of an I-on/I-off similar to 10(7)-10(8) and a subthreshold slope of 66 mV/dec, similar to those formed by a normal process with an optimized sidewall spacer. NMOSFETs with DySi2-x S/D have similar to3 orders of magnitude larger I-off than that of PMOSFETs and show two slopes in the subthreshold region, resulting in the I-on/I-off similar to 10(5) at low drain voltage. It can be attributed to the relatively higher barrier height (Phi(n)) of DySi2-x/n-Si than that of PtSi/p-Si (Phi(p)) and the rougher DySi2-x film. Adding a thin intermediate Ge layer (similar to1nm) between Dy and Si can improve the film morphology significantly. As a result, the improved performance of N-MOSFET is observed. (C) 2004 Published by Elsevier Ltd.
Microwave coplanar filters on Si substrates
(2003)
Chan, KT
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Chin, A
;
Kuo, JT
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Chang, CY
;
Duh, DS
High performance band-pass and band-stop microwave coplanar filters operating from 22 to 94 GHz have been realized on Si substrate using proton implantation process. Very good insertion loss and filter characteristics close to ideal E-M simulation are. measured that demonstrates the excellent filter performance to 91 GHz.
N-type Schottky barrier source/drain MOSFET using ytterbium silicide
(2004-08-01)
Zhu, SY
;
Chen, JD
;
Li, MF
;
Lee, SJ
;
Singh, J
Ytterbium silicide, for the first time, was used to form the Schottky barrier source/drain (S/D) of N-channel MOSFETs. The device fabrication was performed at low temperature, wich is highly preferred in the establishment of Schottky barrier S/D transistor (SSDT) technology, including the HfO2 gate dielectric, and HaN/TaN metal gate. The YbSi2-x, silicided N-SSDT has demonstrated a very promising characteristic with a recorded high I-on/I-off ratio of similar to10(7) and a steep subthreshold slope of 75 mV/dec, which is attributed to the lower electron barrier height and better film morphology of the YbSi2-x/Si contact compared with other self-aligned rare earth metal-(Erbium, Terbium, Dysprosium) silicided Schottky junctions.