Browsing by Author "Pan, FM"

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A bilayer Ti/Ag ohmic contact for highly doped n-type GaN films
(1996-01-08)
Guo, JD
;
Lin, CI
;
Feng, MS
;
Pan, FM
;
Chi, GC
Ohmic contacts with low resistance are fabricated on n-type GaN films using Ti/Ag bilayer metallization. The GaN films are grown by low pressure metalorganic chemical vapor deposition (LP-MOCVD) with Si as the dopant. Ohmic characteristics are studied for films with carrier concentration range from 1.5 x 10(17) to 1.7 x 10(19) cm(-3). The lowest value for the specific contact resistivity of 6.5 x 10(-5) Ohm cm(2) is obtained without annealing. The barrier height of Ti on GaN is calculated to be 0.067 eV. (C) 1996 American Institute of Physics.
Alkylation of nanoporous silica thin films by high density plasma chemical vapor deposition of a-SIC : H
(2004-05-01)
Pan, FM
;
Wu, BW
;
Cho, AT
;
Tsai, KC
;
Tsai, TG
Film stacks of a-SiC:H and molecularly templated nanoporous silica thin films have been prepared, and alkylation of pore surfaces of the nanoporous silica layer by the a-SiC:H layer was studied. The a-SiC:H thin films were deposited by high-density plasma chemical vapor deposition (HDP-CVD) using trimethylsilane (3MS) as the precursor. Carbon is found to uniformly distribute in the thin nanoporous silica film, and the carbon content in the nanoporous film decreases with increasing the a-SiC:H deposition temperature. We used the modified Sanderson formalism to estimate the corresponding Si(2p) and C(1s) electron energies in x-ray photoelectron spectra (XPS) for possible terminal species on pore surfaces in the nanoporous silica layer. According to the XPS analysis and thermal desorption mass spectroscopy, the terminal species are probably in the chemical form of alkoxyl structures. The alkoxyl terminal groups introduced into the nanoporous silica thin film are believed to stem from hydrocarbons trapped in microvoids in the a-SiC:H film, which are formed during the HDP-CVD deposition. The terminal alkoxyl groups in the nanoporous silica layer can greatly enhance the hydrophobicity of the nanoporous silica dielectric, and hence improve the dielectric property of the film stack of a-SiC:H/nanoporous silica. An effective dielectric constant smaller than 1.7 can be obtained for the film stacks. (C) 2004 American Vacuum Society.
An investigation of scanning capacitance microscopy on iron-contaminated p-type silicon
(2001-09-01)
Chang, MN
;
Chang, TY
;
Pan, FM
;
Wu, BW
;
Lei, TF
Scanning capacitance microscopy (SCM) is employed to examine iron-contaminated p-type Si samples. For slightly contaminated samples, a dc voltage of -0.8 V, applied between the sample and the conductive tip, induces positive trapped charges. Owing to the existence of these charges, the region containing trapped charges exhibits an obviously low dC/dV signal. According to contact-mode atomic force microscopy results, the surface, morphology has little effect on the SCM signal. The experimental results indicate that SCM is capable of detecting the distribution of oxidation-related. defects which cannot otherwise be easily observed by atomic force microscopy and transmission electron microscopy. (C) 2001 The Electrochemical Society.
Annealing effects on the interfacial reactions of Ni on Si0.76Ge0.24 and Si1-x-yGexCy
(2000-01-01)
Luo, JS
;
Lin, WT
;
Chang, CY
;
Shih, PS
;
Pan, FM
Interfacial reactions of Ni/Si0.76Ge0.24 and Ni/Si1-x-yGexCy by vacuum annealing and pulsed KrF laser annealing were studied. Upon annealing at a temperature of 200-600 degrees C Ge segregation occurred with the extent becoming more severe at higher temperatures. The temperatures at which phase transformation and the agglomeration structure occurred were higher for Ni/Si1-x-yGexCy than for Ni/Si0.76Ge0.24. Upon pulsed KrF laser annealing the agglomeration structure was considerably improved, however, the retardation of phase transformation in the Ni/Si1-x-yGexCy system still occurred. C accumulation around the original amorphous/crystal interface formed by Cf implantation played a significant effect on delaying the phase transformation. For the Ni/Si0.76Ge0.24 and Ni/Si1-x-yGexCy samples annealed at 0.2 J/cm(2) for 20 and 30 pulses, respectively, smooth Ni(Si0.76Ge0.24)(2) and Ni(Si1-x-yGexCy)(2) films could be grown, meanwhile Ge segregation and strain relaxation of the unreacted Si0.76Ge0.23 films were effectively suppressed. (C) 2000 American Vacuum Society. [S0734-2101(00)04301-3].
Anodic aluminum oxide template assisted growth of vertically aligned carbon nanotube arrays by ECR-CVD
(2004-11-01)
Chen, PL
;
Chang, JK
;
Kuo, CT
;
Pan, FM
;
材料科學與工程學系
Highly aligned carbon nanorubes (CNTs) have been successfully grown in vertical channels of the anodic aluminum oxide (AAO) template by microwave plasma electron cyclotron resonance chemical vapor deposition (ECR-CVD). Nanoporous AAO templates with hexagonal pore pattern were prepared by the two-step anodization of A] films. Following the electroplating of Co catalyst into the pore bottom, multiwalled CNTs were synthesized in the ECR-CVD system using a gas mixture of CH4 and H-2. The microstructure of the CNTs was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The CNTs with a very high packing density and a uniform size distribution are well graphitized, and Co particles embedded at their tips implies the tip growth mechanism. The segments of CNTs stretching out of the AAO nanopores still maintain relatively good alignment, and have a very slow growth rate, which allows us to obtain reproducible tube length by tuning the growth time. Field emission measurements of the CNTs showed derivable electron emission properties, attributed to their uniformity in size, good alignment, and good graphitization properties. (C) 2004 Elsevier B.V. All rights reserved.
Anomalous selective tungsten growth by chemical vapor deposition
(1996)
Mei, YJ
;
Chang, TC
;
Sheu, JD
;
Yeh, WK
;
Pan, FM
Selective tungsten chemical vapor deposition (W-CVD) is one of the most attractive technique for filling deep submicron contact hole and via hole for the ULSI application. In this work, we firstly find out the anomalous selective W growth for the contact hole. The tungsten only nucleates from the side ring of the contact hole bottom. Several predeposition treatments prior to W growth can improve this anomalous feature and excellently selective W growth can be achieved. Auger electron spectroscopy (AES) is utilized to investigate the interface of Si/W. A model has been proposed to explain this anomalous selective tungsten growth.
Characterization of boron silicide layer deposited by ultrahigh-vacuum chemical-vapor deposition
(1996-11-01)
Tseng, HC
;
Pan, FM
;
Chang, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Deposition of a boron-containing layer using B2H6 diluted with H-2 on a Si(001) surface has been carried out in an ultrahigh-vacuum chemical-vapor-deposition (UHV-CVD) system. The deposited boron-containing layers were characterized by atomic force microscope and Auger electron spectroscopy (AES), and the junction depth was determined by secondary-ion-mass spectroscopy. Effective doping is accomplished before perceivable nucleation is initiated. Islands are first formed on the substrate surface at a small dose of diborane, and the grains coalesce to form a rough him for higher doses. At growth temperature above 800 degrees C, the film is composed of possibly SiB6, according to AES depth profiles. Correlation between the junction depth and the sheet resistance of the UHV-CVD-deposited specimens prepared under various conditions is discussed. Postdeposition rapid thermal annealing was performed to study the effect of subsequent thermal cycles on the junction depth and sheet resistance. (C) 1996 American Institute of Physics.
Characterization of Si1-x-yGexCy films grown by C+ implantation and subsequent pulsed laser annealing
(1999-07-15)
Luo, JS
;
Lin, WT
;
Chang, CY
;
Shih, PS
;
Pan, FM
Epitaxial Si1-x-yGexCy films have been grown by C+ implantation into Si0.76Ge0.24 films with a dose of 1.0 x 10(16)/cm(2) and subsequent pulsed KrF laser annealing at an energy density of 0.3-1.6 J/cm(2). Upon laser annealing Ce segregation to the film surface and diffusion to the underlying Si appeared at energy densities above 0.8 J/cm(2) and 1.4 J/cm(2), respectively while the depth profiles of C remained nearly unchanged as in the as-implanted Si1-x-yGeyCy film. Concurrently, no SiC and twin were observed. The amount of C incorporated into substitutional sites initially increased with the energy density in the range of 0.3-1.0 J/cm(2), and then saturated at an energy density of 1.0-1.6 J/cm(2). For the Si1-x-yGexCy films grown at 1.0 J/cm(2) for 5 and 20 pulses SiC was formed with its amount increasing with the pulse number because of C segregation to the film surface and the original amorphous/crystal interface where the EOR defects were present. For the Si1-x-yGexCy films grown at energy densities below 1.0 J/cm(2) the reduction of tensile stress mainly resulted from the effect of substitutional carbon incorporation. (C) 1999 Elsevier Science S.A. All rights reserved.
Characterization of TiN film grown by low-pressure-chemical-vapor-deposition
(1997-10-31)
Mei, YJ
;
Chang, TC
;
Hu, JC
;
Chen, LJ
;
Yang, YL
Conformal TiN films were deposited by thermal low-pressure-chemical-vapor-deposition (LPCVD) in a rotating disk reactor, using TiCl4 and NH3 with N-2 as a dilution gas. TiN plug with 0.05 mu m contact size was achieved. No void formation was observed in the TiN plug. The result demonstrated that LPCVD-TiN can be used to fill very small contact holes. The excellent step coverage and uniformity resulted from a surface-reaction-rate-limited deposition. The resistivity of TiN film was reduced to 133 mu Omega cm by in-situ NH3 plasma post-treatment. The concentration of chlorine in the TiN him was measured to be less than 2 atomic % (at.%) by Auger electron spectroscope measurement. For Al deposited on TiN, the Al orientation was found to be dependent on the deposition method of Al film, but not on the underlying TiN orientation. (C) 1997 Elsevier Science S.A.
Cu contamination effect in oxynitride gate dielectrics
(2001-11-01)
Lin, YH
;
Pan, FM
;
Liao, YC
;
Chen, YC
;
Hsieh, IJ
We have studied the effect of Cu contamination in oxynitride gate dielectrics. Compared to thermal SiO2 with a physical thickness of 3-5 nm, the oxynitride shows a much improved Cu contamination resistance. Furthermore, the Cu contamination resistance increases with increasing nitrogen content. The mechanism of improved gate dielectric resistance to Cu is due to the strong diffusion barrier properties of oxynitride as observed by secondary ion mass spectroscopy. (C) 2001 The Electrochemical Society.
Effect of trimethylsilylation on the film stress of mesoporous silica ultralow-k film stacks
(2006)
Chen, JY
;
Pan, FM
;
Lin, DX
;
Cho, AT
;
Chao, KJ
The film stress of the ultralow-k mesoporous silica thin film and the alpha-SiC:H/ mesoporous silica film stack was studied. The as-calcined mesoporous silica exhibits a tensile film stress due to its volume contraction during bake and calcination. Trimethylsilylation of the mesoporous film results in a spring-back effect and thereby improves the mechanical properties of the porous film. Deposition of a plasma-assisted alpha-SiC:H layer on the mesoporous silica thin film can also relieve the tensile stress, and even made the film stack become compressively stressed. This is ascribed to the stress compensation and alkoxylation occurring during the alpha-SiC:H deposition.
Effective repair to ultra-low-k dielectric material (k-2.0) by hexamethyidisilazane treatment
(2002-07-01)
Mor, YS
;
Chang, TC
;
Liu, PT
;
Tsai, TM
;
Chen, CW
O-2 plasma ashing is commonly used to remove photoresist. The effect of O-2 plasma ashing on the porous organosilicate glass (CH3SiO1.5)(n), one of the spin-on materials, is investigated. O2 plasma can oxidize the methyl groups in porous organosilicate glass (POSG), which leads to the formation of Si-OH groups. The hydrophilic Si-OH groups will induce moisture uptake so that electrical degradation will occur in POSG film. Pure hexamethyldisilazane (HMDS) vapor (100% HMDS) can react with the Si-OH groups in POSG film. It converts hydrophilic Si-OH groups into hydrophobic Si-O-Si(CH3)(3) groups against moisture uptake. The leakage current density decreases by a factor of 2-3 and the dielectric constant decreases from 3.62 to 2.4 when O-2 plasma-damaged POSG undergoes HMDS treatment at 80degreesC for 15 min. Therefore, HMDS treatment is the effective technique to repair the electrical degradation to POSG film during photoresist stripping processing. (C) 2002 American Vacuum Society.
Effective strategy for porous organosilicate to suppress oxygen ashing damage
(2002-03-01)
Liu, PT
;
Chang, TC
;
Mor, YS
;
Chen, CW
;
Tsai, TM
Photoresist stripping with oxygen plasma ashing destroys numerous functional groups in porous organosilicate glasses (OSGs), This impact makes the porous OSG relatively hydrophilic and causes low-k dielectric degradation, To mitigate these issues, various strategies are investigated to enhance oxygen plasma resistance of the porous OSG. These include physical and chemical procedures. Both structural and electrical analyses are used to determine their efficiency. In addition, an optimum prescription that consists of H, plasma and chemical trimethylchlorosilane treatment is developed in this work. The enhancement of oxygen plasma resistance can provide the porous OSG for practical application in the multilevel interconnection. (C) 2002 The Electrochemical Society.
Effects of isolation materials on facet formation for silicon selective epitaxial growth
(1997-10-20)
Tseng, HC
;
Chang, CY
;
Pan, FM
;
Chen, JR
;
Chen, LJ
Effects of isolation materials on facet formation for low temperature Si selective epitaxial growth (SEG) using Si2H6 have been demonstrated by ultrahigh vacuum-chemical molecular epitaxy (UHV-CME) system. The activation energy of the Si epitaxial growth is 47.35 Kcal/mol. The isolation material includes silicon nitride, wet oxide, and tetraethylorthosilicate (TEOS) oxide. Different isolation materials have different faceting behaviors for the Si epilayer. A silicon nitride mask and a wet oxide mask result in a preferred faceting plane of (111) and (311), respectively. Using a TEOS oxide mask, we obtain a low temperature Si SEG layer without facet and twin formation, The preferred faceting plane orientation for different isolation materials is ascribed to the difference in the interface free energy between the Si layer and the isolation material. (C) 1997 American Institute of Physics.
Effects of isolation oxides on undercut formation and electrical characteristics for silicon selective epitaxial growth
(1997-06-01)
Tseng, HC
;
Chang, CY
;
Pan, FM
;
Chen, LP
;
電子工程學系及電子研究所
Three isolation oxide structures have been prepared to study their resistance to the undercut formation during selective epitaxial growth (SEG) processes. The N2O annealed oxide tetraethyoxysilane (TEOS) oxide stacked structure has the best resistance to the undercut formation and exhibits the best electrical characteristics compared to the other two isolation oxide structures prepared in the study, which are a wet oxide and a TEOS oxide. This is ascribed to a smaller interfacial stress between the isolation oxide and the silicon substrate for the stacked structure. The sidewall damage is the predominant factor deteriorating the current-voltage (I-V) characteristics of the N+-P SEG diodes. When treated with a quick HF dip and followed by a low temperature desorption cleaning before the SEG process, the N+-P SEG diode, which has no perceivable undercut, shows satisfactory I-V characteristics.
Effects of isolation oxides on undercut formation and electrical characteristics for silicon selective epitaxial growth
(1997-06-01)
Tseng, HC
;
Chang, CY
;
Pan, FM
;
Chen, LP
;
電子工程學系及電子研究所
Three isolation oxide structures have been prepared to study their resistance to the undercut formation during selective epitaxial growth (SEG) processes. The N2O annealed oxide tetraethyoxysilane (TEOS) oxide stacked structure has the best resistance to the undercut formation and exhibits the best electrical characteristics compared to the other two isolation oxide structures prepared in the study, which are a wet oxide and a TEOS oxide. This is ascribed to a smaller interfacial stress between the isolation oxide and the silicon substrate for the stacked structure. The sidewall damage is the predominant factor deteriorating the current-voltage (I-V) characteristics of the N+-P SEG diodes. When treated with a quick HF dip and followed by a low temperature desorption cleaning before the SEG process, the N+-P SEG diode, which has no perceivable undercut, shows satisfactory I-V characteristics.
Effects of morphology and surface characteristics of poly(imide siloxane)s and deep UV/O-3 surface treatment on the interfacial adhesion of poly(imide siloxane)/alloy-42 leadframe joints
(1999-07-01)
Jwo, SL
;
Whang, WT
;
Hsieh, TE
;
Pan, FM
;
Liaw, WC
The effect of surface characteristics and morphology of poly(imide siloxane) (PIS) on the true interfacial adhesion between PIS films and alloy-42 substrates was studied. The effect of the viscosity of PIS films and the surface treatment of deep UV/O-3 (d-UV/O-3) on alloy-42 plates on the peel strength of PIS films/alloy-42 joints has also investigated. 3,3',4,4'-benzophenone tetracarboxylic dianhydride/2,2'-bis[4-(3-aminophenoxy)phenyl]sulfone (BTDA/m-BAPS) based PIS films with alpha,omega-bis(3-aminopropyl)polydimethyl siloxane (APPS) molecular weight M-n = 996 g/mole (PIS9Siy) show two phases in all compositions and the linear dependence of the critical surface tension on the surface concentration of the silicon, [Si-surf], on the PIS films. The PIS films with the APPS M-n = 507 g/mole (PIS5Siy) or M-n = 715 g/mole (PIS7Siy) exhibit a morphology change from a homogeneous phase to an inhomogeneous phase starting at the mole ratio (y) of APPS/PIS = 2.7% and 1.1%, respectively. The curves of critical surface tension dependence on the [Si-surf] discontinue or deflect at these two compositions, respectively. The treatment of d-UV/O-3 on alloy-42 plates improves the wetting on the alloy surface and promotes the peel strength between the PIS films and alloy-42 plates by a magnitude of greater than or equal to 20%. These results show that the flowability of the same PIS films bonding at different temperatures significantly affects the bonding strength of the joints, but the flowability of different PIS films bonding at the same temperature, e.g. 400 degrees C, is not the key factor governing the bonding strength of the joints. The true interfacial adhesion of the PIS5Si0.6/alloy-42 joint is 80% higher than that of the unmodified BTDA/m-BAPS based polyimide film/alloy-42 joint. However, zero true interfacial adhesion is obtained between the PIS9Siy films and alloy-42 plates. The wetting kinetics experiment shows that the higher the siloxane content in the PIS, the higher the activation energy for the adhesive bonding process. Moreover, the phase sepration significantly increases the activation energy. The scanning electron micrographs of the peeled-off PIS film surfaces from the PIS/alloy-42 joints reveal the rougher surface morphology from the sample with the higher interfacial adhesion.
Eliminating dielectric degradation of low-k organosilicate glass by trimethylchlorosilane treatment
(2002-07-01)
Chang, TC
;
Liu, PT
;
Mor, YS
;
Tsai, TM
;
Chen, CW
The interaction between low-k organosilicate glass (OSG) and photoresist removal is investigated. O-2 plasma ashing and chemical wet stripper are commonly performed to remove photoresist (PR) in integrated circuit fabrication. However, O-2 plasma or wet stripper will attack function groups and cause Si-OH group formation in OSG film during PR removal processing. The Si-OH groups often lead to moisture uptake and consequently dielectric degradation will occur in OSG film. Trimethylchlorosilane (TMCS) treatment can negate the damage in the OSG film after the PR removal process. In addition, chemical TMCS can react with Si-OH groups and reduces moisture uptake so that the dielectric characteristic of OSG can be maintained. Hence, TMCS treatment is a promising method for photoresist removal. (C) 2002 American Vacuum Society.
Emission of bright blue light from mesoporous silica with dense Si (Ge) nanocrystals
(2005)
Cho, AT
;
Shieh, JM
;
Shieh, J
;
Lai, YF
;
Dai, BT
Three-dimensional Si (Ge) nanocrystals (NCs) were dispersed within the nanopores of mesoporous silica films by high-density plasma (HDP), low-density plasma, or implantation. Surface states of the resulting Si (Ge) NCs/silica arrays initiate blue-white photoluminescence (PL). HDP makes reactive species highly mobile and enables deposited NCs bonded with pore-wall well, therefore, efficiently constructing photoemission arrays. The mean density of HDP-synthesized semiconducting NCs is as high as 1 x 10(18)/cm(3). Accordingly, blue PL of arrays obtained with HDP, which is 4- 7 times stronger than those obtained with other methods, exhibits quantum-efficiency of 1%, near the reported value for green-to-red light emission from quantum-confined Si NCs. © 2005 The Electrochemical Society. All rights reserved.
Fabrication and field emission characteristics of highly ordered titanium oxide nanodot arrays
(2005)
Chen, PL
;
Huang, WJ
;
Chang, JK
;
Kuo, CT
;
Pan, FM
A field emission triode device has been fabricated using self-organized nanodot arrays as the electron emission source. Uniform nanodot arrays of titanium oxide were prepared from the Al/Ti film stack on silicon substrates by electrochemical anodization. The field emission triodes with titanium oxide nanodot emitters exhibited a low gate turn-on voltage of 45 V and high emission current density of 25 mA/cm(2) at 120 V. The excellent electric properties and easily controllable fabrication process of the nanodot triodes show potential applications for field emission displays and vacuum microelectronics. (c) 2005 The Electrochemical Society.