Browsing by Author "Lin, DS"

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A 1.8 V, 10 Gbps fully integrated CMOS optical receiver analog front end
(2004)
Chen, WZ
;
Cheng, YL
;
Lin, DS
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A fully integrated 10 Gbps optical receiver analog front-end, includes a trans-impedance amplifier (TIA) and a limiting amplifier (LA), is fabricated using a 0.18 mum CMOS technology. The receiver front-end provides a conversion gain up to 85 dBOmega and -3 dB bandwidth of 7.6 GHz. The sensitivity of the optical receiver is - 13 dBm at a bit-error rate of 10(-12) with 2(31)-1 pseudo-random bits. 3-D symmetric transformers are utilized in the AFE design for bandwidth enhancement.
A 1.8-V 10-Gb/s fully integrated CMOS optical receiver analog front-end
(2005-06-01)
Chen, WZ
;
Cheng, YL
;
Lin, DS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A fully integrated 10-Gb/s optical receiver analog front-end (AFE) design that includes a transimpedance amplifier (TIA) and a limiting amplifier (LA) is demonstrated to require less chip area and is suitable for both low-cost and low-voltage applications. The AFE is fabricated using a 0.18-mu m CMOS technology. The tiny photo current received by the receiver AFE is amplified to a differential voltage swing of 400 mV((pp)). In order to avoid off-chip noise interference, the TIA and LA are dc-coupled on the chip instead of ac-coupled though a large external capacitor. The receiver front-end provides a conversion gain of up to 87 dB Omega and -3 dB bandwidth of 7.6 GHz. The measured sensitivity of the optical receiver is -12 dBm at a bit-error rate of 10(-12) with a 2(31) -1 pseudorandom test pattern. Three-dimensional symmetric transformers are utilized in the AFE design for bandwidth enhancement. Operating under a 1.8-V supply, the power dissipation is 210 mW, and the chip size is 1028 mu m x 1796 mu m.
Atomic-level investigation of the growth of Si/Ge by ultrahigh vacuum chemical vapor deposition
(1997-05-01)
Lin, DS
;
Miller, T
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Chiang, TC
;
物理研究所
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Institute of Physics
Si and Ge films can be prepared under ultrahigh vacuum conditions by chemical vapor deposition using disilane and digermane as source gases. These gases offer a high sticking probability, and are suitable for atomic layer epitaxy. Using synchrotron radiation photoemission spectroscopy and scanning tunneling microscopy, we have examined the surface processes associated with the heteroepitaxial growth of Ge/Si. The measured surface-induced shifts and chemical shifts of the Si 2p and Ge 3d core levels allow us to identify the surface species and to determine the surface chemical composition, and this information is correlated with the atomic features observed by scanning tunneling microscopy. Issues related to precursor dissociation, attachment to dangling bonds, diffusion, surface segregation, growth morphology, and pyrolytic reaction pathways will be discussed. (C) 1997 American Vacuum Society.
Atomistic view of the recombinative desorption of H(2) from H/Si(100)
(2005-05-20)
Ferng, SS
;
Lin, CT
;
Yang, KM
;
Lin, DS
;
Chiang, TC
Scanning tunneling microscopy is employed to investigate the recombinative desorption of H(2) from hydrogenated Si(100) surfaces consisting of dihydride (SiH(2)) and monohydride (SiH) surface species organized in (1x1), (3x1), and (2x1) configurations. The results show that desorption from dihydrides involves a pair of neighboring dihydrides linked along the tetrahedral bond direction. Dihydrides in (3x1) domains are separated in the same direction by monohydrides, and desorption from a pair is geometrically impossible. The same desorption mechanism nevertheless applies via first a position switching of dihydrides with neighboring monohydrides.
Atomistic view of the recombinative desorption of H-2 from H/Si(100)
(2005-05-20)
Ferng, SS
;
Lin, CT
;
Yang, KM
;
Lin, DS
;
Chiang, TC
Scanning tunneling microscopy is employed to investigate the recombinative desorption of H-2 from hydrogenated Si(100) surfaces consisting of dihydride (SiH2) and monohydride (SiH) surface species organized in (1x1), (3x1), and (2x1) configurations. The results show that desorption from dihydrides involves a pair of neighboring dihydrides linked along the tetrahedral bond direction. Dihydrides in (3x1) domains are separated in the same direction by monohydrides, and desorption from a pair is geometrically impossible. The same desorption mechanism nevertheless applies via first a position switching of dihydrides with neighboring monohydrides.
Atomistics of Ge deposition on Si(100) by atomic layer epitaxy
(2003-01-31)
Lin, DS
;
Wu, JL
;
Pan, SY
;
Chiang, TC
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物理研究所
Chlorine termination of mixed Ge/Si(100) surfaces substantially enhances the contrast between Ge and Si sites in scanning tunneling microscopy observations. This finding enables a detailed investigation of the spatial distribution of Ge atoms deposited on Si(100) by atomic layer epitaxy. The results are corroborated by photoemission measurements aided by an unusually large chemical shift between Cl adsorbed on Si and Ge. Adsorbate-substrate atomic exchange during growth is shown to be important. The resulting interface is thus graded, but characterized by a very short length scale of about one monolayer.
Chlorine-induced Si surface segregation on the Ge-terminated Si/Ge(100) surface from core-level photoemission
(2001-12-15)
Lin, DS
;
Pan, SY
;
Wu, MW
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物理研究所
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Institute of Physics
This study investigated the thermal reactions on the Cl-terminated Si/Ge(100)-2x1 surface using synchrotron radiation photoemission spectroscopy. Populations of surface Cl-Ge and CI-Si bonds during annealing are monitored by measuring the intensities of their corresponding Ge 3d, Si 2p, and Cl 2p core-level components. Experimental results clearly demonstrate that no Si atoms are present on the surface after the deposition of 0.8 monolayer Si on the Ge(100) surface at 730 K and that CI termination pulls out the indiffused Si of about two atomic layers deep to form Cl-Si bonds upon annealing at 550-690 K. We attribute such chlorine induced Si segregation to a thermodynamic driving force that favors the CI-Si surface species. Above 680 K, chlorine is desorbed in the form of SiCl2, although the top surface layer of the starting Si/Ge(100) sample consists of Ge-Ge dimers only.
Comment on "Atomistic view of the recombinative desorption of H-2 from H/Si(100)" - Reply
(2006-05-26)
Lin, DS
;
Chiang, TC
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物理研究所
;
Institute of Physics
Comparison of thermal reactions of phosphine on Ge(100) and Si(100) by high-resolution core-level photoemission
(2001-06-20)
Tsai, HW
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Lin, DS
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物理研究所
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Institute of Physics
The thermal decomposition processes of phosphine (PH;) on a Ge(I 0 0)-2 x I surface at temperatures between 325 and 790 K were investigated and compared with those on Si(I 0 0)-2 x 1. High-resolution synchrotron radiation core-level photoemission spectra indicates that. at room temperature phosphine molecularly adsorbs on the Ge(I 0 0)-2 x I surface, however on the Si(1 0 0)-2 x I it partially dissociates into PH2 and H. Successive annealing of the PH3-saturated Si(1 0 0) and Ge(I 0 0) surfaces at higher temperatures similarly converts PH3 into PH2 and PH2 to P. P atoms form stable P-P and/or P-Si dimers on Si(I 0 0) above 720 K. but exhibit complex bonding configurations on Ge(1 0 0). (C) 2001 Elsevier Science B.V. All rights reserved.
Coverage-dependent thermal reactions of digermane on Si(100)-(2x1)
(1996-12-15)
Lin, DS
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Huang, KH
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Pi, TW
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Wu, RT
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物理研究所
In this study, we examine the adsorption and thermal reactions of digermane (Ge6H6) on the Si(100)-(2X1) surface with high-resolution core-level photoemission spectroscopy using synchrotron radiation. At 325 K, the digermane dissociatively chemisorbed to produce GeH3, GeH2, GeH, and SiH species. The sticking coefficient at zero coverage deduced from the photoemission intensity is similar to 0.5. Successive annealing of rhc digermane-saturated surface tc, higher temperatures causes further decomposition of GeH3 and GeH2 and the desorption H from GeH and SiH, leaving atomic Ge on the surface. In light of the sufficiently large chemical and surface shifts in their core-level binding energies fur different surface species, those processes were identified by examining the evolution of Ge 3d and Si 2p line shapes. Experimental results indicate that the reaction for H release from GeH not only occurred in a large temperature range but also depended heavily on the Ge2H6 adsorption coverages. To reaction routes for H release from Ge sites were used to describe the large reaction temperature spreads accurately. GeH decomposition by transferring the H atom to a surface Si dangling bond took place for low coverages at less than or equal to 590K, and H-2 thermal desorption occurred for higher coverages in the range of 590-770 K. The former process of atom transfer of H from Ge to Si sites was directiy observed in the Ge 3d and Si 2p photoemission spectra.
Distribution of dangling bond pairs on partially hydrogen-terminated Si(100) surface observed by scanning tunneling microscopy
(2000-05-20)
Chen, RP
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Lin, DS
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物理研究所
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Institute of Physics
Hydrogen recombinative desorption from a Si2H2 monohydride dimer on the Si(100) surface regenerates a dangling bond (DB) pair on the dimer. In this paper, we investigated the spatial distribution of the regenerated DB pairs on the Si(100)-2 x 1:H and disilane-passivated Si(100) surface using elevated temperature scanning tunneling microscopy (HT-STM) in the temperature range between 590 and 622 K. Experimental results indicate that the ends of one-dimensional (1D) monohydride dimer islands are preferred sites for DB pairs and a repulsive interaction occurs between two neighboring DB pairs in the same dimer row. (C) 2000 Elsevier Science B.V. All rights reserved.
Evolution of two-dimensional structure phase transitions (3 x 1) -> (2 x 1) and (1 x 1) -> (2 x 1) on hydrogen-terminated Si(100) surface
(2006-03-01)
Ferng, SS
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Lin, CT
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Yang, KM
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Hsieh, MF
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Lin, DS
On the Si(100) surface, monohydride dimers (H-Si-Si-H or M-M) and dihydride (H-Si-H or D) species can form an ordered mixture with (3 x 1), (1 x 1) and (2 x 1) phases. Thermal annealing at elevated temperatures causes both the (3 x 1) and (1 x 1) domains to transform to the (2 x 1) monohydride phase. We utilize scanning tunneling microscopy to observe these two-dimensional structure phase transitions on the atomic scale. The results show that the coverage of the (3 x 1) and (1 x 1) domains decays linearly with a common half-life time of similar to 9.8 It at 570 K. In good agreement with a previous report, this finding suggests that the two different transitions are governed by the same reaction mechanism, i.e., the dihydride-pair recombination mechanism.
Gallium K-edge EXAFS study of GaN : Mg films
(2000)
Pan, YC
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Wang, SF
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Lee, WH
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Lin, WC
;
Shu, CK
Ga K-edge extended X-ray absorption fine structure (EXAFS) measurement was employed to investigate the local structure of GaN:Mg films grown by metalorganic vapor phase epitaxy (MOVPE) with various Cp,Mg dopant flow rates using both in-plane and out-of-plane polarization modes of X-ray. The near edge absorption spectra were found to depend on X-ray polarization strongly for undoped GaN sample and weakly to minutely for heavily Mg-doped and amorphous films. The results indicate Mg incorporation modifies the local structure around the absorber Ga atom and, hence, alters the molecular orbital electron transition of GaN sample. EXAFS analysis showed both vacancy and Mg-interstitial defects contribute to the reduction of coordination numbers along the hexagonal c-axis of GaN:Mg film.
Gallium K-edge x-ray absorption study on Mg-doped GaN
(2001-01-01)
Pan, YC
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Wang, SF
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Lee, WH
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Lee, MC
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Chen, WK
Ga K-edge x-ray absorption measurements were employed to investigate Mg-doping effects in GaN samples. Strong polarization-dependent x-ray absorption near-edge structures become less pronounced with increasing doping concentration, indicating the formation of a mixing-phase structure of cubic and hexagonal phases. Analysis of the extended x-ray absorption region of the spectra revealed doping-related defects such as vacancies, substitutions, and interstitial occupations. They were formed anisotropically in the crystal c axis direction and its perpendiculars. Disorderliness arising from phase mix and defects is believed to have lowered the Debye temperature of the doped GaN films and caused the destructive interference of the absorption fine-structure oscillation functions. These effects were taken into account for the observed large coordination number reductions in our samples. (C) 2001 American Institute of Physics.
Growth mode in Si(100)-(2x1) epitaxy by low-temperature chemical-vapor deposition
(1998-05-15)
Wu, PH
;
Lin, DS
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物理研究所
;
Institute of Physics
This study investigates the growth processes of Si on Si(100)-(2x1) during ultrahigh vacuum chemical vapor deposition using disilane as the source gas. The evolution of surface morphology and atomic ordering during growth at temperatures between 300 and 600 degrees C is examined in real time by high-temperature scanning tunneling microscopy. Directly imaging various growth kinetic processes, such as pure step-flow growth, double step-flow growth, two-dimensional nucleation growth, and surface passivation at different substrate temperature ranges clearly illustrates the growth mechanisms for the model chemical vapor deposition growth system and provides interesting comparison with results of Monte Carlo simulations and those of solid phase molecular-beam epitaxy. [S0163-1829(98)05619-7].
Growth process of Ge on Si(100)-(2x1) in atomic-layer epitaxy from Ge2H6
(1997-08-15)
Huang, KH
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Ku, TS
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Lin, DS
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物理研究所
;
Institute of Physics
This study investigates the growth process of Ge on Si(100) during atomic-layer epitaxy (ALE) utilizing digermane. The surface ordering, morphology, and stoichiometry of the digermane saturated Si(100) surface at temperatures between 300 and 900 K, as well as the grown films are examined both by scanning tunneling microscopy (STM) and high-resolution core-level photoemission spectroscopy employing synchrotron radiation. An exposure of more than 15 L (1 L=10(-6) T s) of digermane on the Si(100)-(2x1) surface at room-temperature results in a saturated and disordered surface. When the digermane saturated surface is heated to 725 K for 60 s, diluted Ge dimer chains are created and surrounded by SiH species. Further annealing to 810 K completely desorbs hydrogen from the surface, leaving large two-dimensional islands covering similar to 41% of its area. The surface recovers its smooth 2x1 structure, but is interspersed with poorly ordered short dimer vacancy lines at 900 K with no observable contrast on the atomic terraces, indicating displacive adsorption of Ge on the terraces. Significant differences of the surface diffusion phenomena between the gas-phase and solid-phase molecular-beam epitaxy (MBE) are observed. Multilayer Si deposition is performed by ALE, i.e., cyclic digermane adsorption at near room temperature, followed by thermal annealing at 900 K. STM images reveal the formation of 2 x n structures and increasing roughening of the surface as the growth cycle increases, similar to what occurs during MBE. Issues related to the atomic origins of surface core-level shifts and the chemical composition of the surface layer resulting from the formation of mixed Ge-Si or Ge-Ge during the submonolayer adsorption of Ge on Si(100) are also discussed.
Hydrogen-desorption kinetic measurement on the Si(100)-2x1 : H surface by directly counting desorption sites
(1999-09-15)
Lin, DS
;
Chen, RP
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物理研究所
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Institute of Physics
The desorption kinetics of hydrogen from the Si(100)-2x1:H monohydride surface was investigated by means of variable-temperature scanning-tunneling microscopy (STM) in the temperature range between 590 and 668 K. By directly counting the number of desorption sites in the STM images for various annealing time at several temperatures, an activation barrier of E-d = 2.22+/-0.20 eV and a pre-exponential factor of nu(d) = 3.4 x 10(13+/-0.3) s(-1) for the H-2 recombinative desorption are deduced. The sequential images acquired in real times show that hydrogen desorbs in a random manner and the interaction between two neighboring paired dangling bond sites is repulsive.
Influence of sapphire nitridation on properties of indium nitride prepared by metalorganic vapor phase epitaxy
(1999-02-01)
Pan, YC
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Lee, WH
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Shu, CK
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Lin, HC
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Chiang, CI
Indium nitride films have been successfully grown on (0001) sapphire substrates by metalorganic vapor phase epitaxy (MOVPE) using TMIn and NH3 as source precursors. Experimental results indicated that pregrowth treatments, such as buffer layer growth, nitridation temperature and nitridation duration have dramatic effects on the growth of the InN films. For films nitridated at 1,000 degrees C for 40 min without any buffer layer growth, we obtained an InN film quality with Hall mobility, carrier concentration and line width of Raman E-2 mode of 270 cm(2)/V.s, 5 x 10(19) cm(-3) and 4.5 cm(-1), respectively, which is among the best quality ever reported for such type of film grown by MOVPE.
Interaction of phosphine with Si(100) from core-level photoemission and real-time scanning tunneling microscopy
(2000-01-15)
Lin, DS
;
Ku, TS
;
Chen, RP
;
物理研究所
;
Institute of Physics
In this paper, we investigate the interaction of phosphine (PH3) on the Si(100)-2 x 1 surface at temperatures between 635 and 900 K. The hydrogen desorption, growth mode, surface morphology, and chemical composition and ordering of the surface layer are examined by synchrotron radiation core-level photoemission and real-time high-temperature scanning tunneling microscopy. The P 2p core-level spectra indicate that decomposition of PHn is complete above similar to 550 K and the maximum P coverage is strongly influenced by the growth temperature, which governs the coverage of H-terminated sites. The scanning tunneling microscopy (STM) images taken at real time during PH3 exposure indicate that a surface phosphorus atom readily and randomly displaces one Si atom from the substrate. The ejected Si diffuses, nucleates, and incorporates itself into islands or step edges, leading to similar growth behavior as that found in Si chemical vapor deposition. Line defects both perpendicular and parallel to the dimer rows are observed on the nearly P-saturated surface. Perpendicular line defects act as a strain relief mechanism. Parallel line defects result from growth kinetics. STM images also indicate that incorporating a small amount of phosphorus eliminates the line defects in the Si(100)-2 x n surface.
Real-time scanning tunneling microscopy observation of Si(100)-(2x1)->(2xn)-> c(4x4) structural phase transitions
(1998-02-01)
Lin, DS
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Wu, PH
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物理研究所
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Institute of Physics
We report on the discovery of Si(100)-(2 x 1)-->(2 x n)-->c(4 x 4) structural phase transitions. Annealing the Si(100)-(2 x 1) surface between 590 and 700 degrees C for some hours causes dimer vacancies to increase and nucleate into chains, ultimately forming the (2 x n) structure. After further annealing. c(4 x 4) areas appear grow. and finally cover the entire surface. Experimental results raise the possibility not only that c(4 x 4) is a stable low-temperature structure of Si(100), but that (2 x 1) is a high-temperature phase stabilized at room temperature owing to its kinetic limitations. (C) 1998 Elsevier Science B.V.