Browsing by Author "Ku, TK"

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A novel technology to reduce the antenna charging effects during polysilicon gate electron-cyclotron-resonance etching
(1996-07-01)
Cheng, HC
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Kang, TK
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Ku, TK
;
Dai, BT
;
Chen, LP
A novel technique, which uses Cl-2/O-2 mixed gas in the electron cyclotron resonance (ECR) etching system, has been proposed to remove the antenna charging effect of the MOS capacitors with 5-nm-thick oxides during polysilicon gate etching. The Cl-2/O-2 can cause the trenching effect and prevents the gate oxide from the charging damage. Furthermore, the ECR system can provide high polysilicon/oxide selectivity so that the Si substrate under gate oxide is not directly bombarded by the ions. Consequently, the E(bd) degradation of the MOS capacitors disappears as the trenching effect is apparent by using moderate Cl-2/O-2 mixed gas.
Characterization and fabrication of chimney-shaped metal field emitters
(1996-01-01)
Cheng, HC
;
Wang, CC
;
Ku, TK
;
Hsieh, IJ
;
電子工程學系及電子研究所
A novel fabrication technology has been successully developed for chimney-shaped metal field emitters in order to improve the electrical characterisitcs of field-emission devices. This technology is based on anisotropic dry etching and sputtering deposition of metal film as well as wet etching of the attached silicon. It enables easy fabrication of chimney-shaped field emitters with excellent uniformity and high reproducibility. The anode current of the chimney-shaped Cr field emitter array (FEA) is 36.3 mu-A at the applied voltage of 1100 V and the threshold voltage V-T, defined as that for which the anode current I-n reaches 1 mu-A is 787 V. The chimney-shaped Cr FEA emits a current thirty times higher than that from the cone-shaped Cr-clad FEA at the applied voltage of 1100 V. This can be attributed to the presence of many sharp tips along the edge of the chimney-shaped emitter. The degradation phenomenon is not observed because compensation occurs between these many sharp tips. Another merit of this technique is that only one photolithography mask is needed during processing.
Enhanced electron emission from phosphorous- and boron-doped diamond-clad Si field emitter arrays
(1996-12-15)
Ku, TK
;
Chen, SH
;
Yang, CD
;
She, NJ
;
Tarntair, FG
A new fabrication technology of polycrystalline diamond-clad Si microtips using microwave plasma chemical vapor deposition (MPCVD) has been developed to improve the characteristics of electron field emission from the pure Si tips. A uniform and smooth coating morphology for the diamond-clad Si tips have been achieved. Electron emission currents of diamond-clad tips are much higher than those of pure Si tips. Such great improvement is attributed to the lowering of the effective work function in the diamond-clad tips. The effects of phosphorus- and boron-doped diamond-clad Si tips have been also studied in comparison with the undoped ones. The current-voltage characteristics of the undoped diamond-clad tips were further enhanced by the in-situ doping of phosphorus or boron due to a higher electron supplement. Moreover, the P-doped diamond-clad tips show a better field emission performance as compared to the B-doped ones. This difference is surmised to be associated with the higher electron conductivity and defect densities of P-doped diamond films.
Enhanced electron emission from phosphorus-doped diamond-clad silicon field emitter arrays
(1996-05-01)
Ku, TK
;
Chen, SH
;
Yang, CD
;
She, NJ
;
Wang, CC
Undoped and phosphorus (P)-doped diamond-clad Si field emitter arrays have been successfully fabricated using microwave plasma chemical vapor deposition (MPCVD) technology. The electron emission from the blunt diamond-clad microtips are much higher than those for the pure Si tips with sharp curvature due to a lower work function, Furthermore, the characteristics of emission current against applied voltage for the P-doped diamond-clad tips show superior emission at lower field to the undoped ones, After the examination of Auger electron spectroscopy (AES) and electrical characteristics of as-grown diamond, such a significant enhancement of the electron emission from the P-doped diamond-clad tips is attributed to a higher electron conductivity and defect densities.
Excellent emission characteristics of tunneling oxides formed using ultrathin silicon films for flash memory devices
(1996-06-01)
Wang, PW
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Ku, TK
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Su, HP
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Hong, G
;
Cheng, HC
A novel technique using oxidized ultrathin rugged polysilicon films on silicon substrates has been appied to significantly improve the tunneling efficiency of thin oxides. As compared with oxidized amorphous silicon films, these rugged polysilicon films can achieve a higher emission current. High-resolution transmission electron microscopy (HRTEM) was used to observe the atomic-scale microtips at the SiO2/Si and polysilicon/SiO2 interfaces. According to the extracted geometry parameters of the microtips, a two-dimensional numerical simulator based on the finite difference method using the curved emitting surface of microtips can well explain the remarkable current asymmetry of the dielectrics. This suggests that the oxidized rugged polysilicon films can form higher microtips and smaller tip angles, resulting in better emission characteristics that will enable potential applications to future 5-V-only nonvolatile memories.
Fabrication and characterization of diamond-clad silicon field emitter arrays
(1995-12-01)
Cheng, HC
;
Ku, TK
;
Hsieh, BB
;
Chen, SH
;
Leu, SY
Microsized silicon tip arrays with sharp curvature were formed based on the techniques including reactive ion etching and oxidation-sbarpening. A new fabrication technology of polycrystalline diamond-clad Si microtips using microwave plasma CVD(MPCVD) was subsequently developed to improve the capability and stability of the field emission from the pure Si tips. By means of SEM and transmission electron microscopy (TEM), the as-deposited films are found to be polycrystalline diamond with fine grain (similar to 800 Angstrom) structure. With the anode voltage of 1100V and anode-to-cathode distance of 30 mu m, the emission current of 240 mu A in a 50 x 50 diamond-clad Si microtip array can be achieved, which is much higher than those for Cr-clad and pure Si microtip arrays. Based on curve fitting of a Fowler-Nordheim (F-N) plot, such great improvement is partially attributed to the lowering of the effective work function from 5.5 eV to 2.08 eV.
Fabrication and characterization of gated Si field emitter arrays with gate aperture below 0.5 mu m
(1995)
Ku, TK
;
Hsieh, BB
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Chen, MS
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Wang, CC
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Wang, PW
Fabrication and characterization of the Pd-silicided emitters for field-emission devices
(1995)
Wang, CC
;
Ku, TK
;
Feng, MS
;
Hsieh, IJ
;
Cheng, HC
Fabrication and characterization of the Pd-silicided emitters for field-emission devices
(1996-06-01)
Wang, CC
;
Ku, TK
;
Hsieh, IJ
;
Cheng, HC
;
電子工程學系及電子研究所
The structure of Pd-silicided held emitters based on the silicon micromachining technology has been demonstrated. The uniform and extremely sharp silicided emitters are formed using wet chemical etching, low-temperature oxidation sharpening (LTOS), metal coating, and furnace annealing. The silicided emitters are firstly identified by the bright-held, dark-held images, and diffraction patterns of transmission electron microscope (TEM). Under the applied voltage of 1100 V, the anode currents of the Pd-coated and silicided emitters are 16 mu A and 26 mu A, respectively. The values of threshold voltage V-T for Pd-coated and silicided emitters are about 745 V and 785 V, respectively. The lower threshold voltage of the Pd-coated emitters is duo to the smaller emission work function of palladium. The emission work function of the Pd-silicided emitters is calculated to be 8.31 eV. Furthermore; the long and short-term current stabilities of silicided emitters is also better than that of Pd-coated ones. These results show that these silicided emitters have potential applications in vacuum microelectronics to obtain superior Lifetime, reliability, and stability.
Fabrication and characterization of the Pd-silicided emitters for field-emission devices
(1996-06-01)
Wang, CC
;
Ku, TK
;
Hsieh, IJ
;
Cheng, HC
;
電子工程學系及電子研究所
The structure of Pd-silicided held emitters based on the silicon micromachining technology has been demonstrated. The uniform and extremely sharp silicided emitters are formed using wet chemical etching, low-temperature oxidation sharpening (LTOS), metal coating, and furnace annealing. The silicided emitters are firstly identified by the bright-held, dark-held images, and diffraction patterns of transmission electron microscope (TEM). Under the applied voltage of 1100 V, the anode currents of the Pd-coated and silicided emitters are 16 mu A and 26 mu A, respectively. The values of threshold voltage V-T for Pd-coated and silicided emitters are about 745 V and 785 V, respectively. The lower threshold voltage of the Pd-coated emitters is duo to the smaller emission work function of palladium. The emission work function of the Pd-silicided emitters is calculated to be 8.31 eV. Furthermore; the long and short-term current stabilities of silicided emitters is also better than that of Pd-coated ones. These results show that these silicided emitters have potential applications in vacuum microelectronics to obtain superior Lifetime, reliability, and stability.
Fabrication and characterization of various carbon-clad silicon microtips with ultra-small tip radii
(2000-02-01)
Tarntair, FG
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Hong, WK
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Ku, TK
;
She, NJ
;
Chen, CF
Various types of ultra sharp Si microtips and multitips with carbon-clading films were fabricated by microwave plasma chemical vapor deposition (MPCVD). The radii of these Si tips prepared by bias assisted carburization (BAC) can he reduced below 300 Angstrom under a low deposition temperature (<550 degrees C). Field emission characterization was performed in a high vacuum environment. With an applied anode voltage of 1100 V, emission currents of 169 mu A, 198 mu A, and 385 mu A can be achieved from an array of 50 x 50 BAG-clad Si monotips, Si multitips via high bias, and Si multitips via the Ar presputtering technique, respectively. Both the auger electron spectroscopy (AES) and X-ray photo-electron spectroscopy (XPS) studies of the C l s peak suggest that the BAC-cladding is more likely to be a carbon-rich SiC layer or a SiC layer mixed with a small amount of diamond nuclei. This BAC-carbon can be used as an effective nucleation layer for further diamond nuclei. Due to the low field emission, low temperature, and large area growth capability, the sharp BAC-clad Si multitip field emitter arrays are attractive Tor flat panel display applications.
Fabrication and characterization of various carbon-clad silicon microtips with ultra-small tip radii.
(1996)
Ku, TK
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Chen, SH
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Yang, CD
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She, NJ
;
Tarntair, FG
In order to take the advantages of diamond and carbon coating on flat-panel display, unscratched sharp Si microtip arrays have been carburized based on the bias enhanced nucleation (BEN) and low-pressure MPCVD deposition to obtain an ultra-sharp carburized Si FEAs. The tip radii of these BEN-carburized Si tips can be reduced below 300 Angstrom under low deposition temperature (<550 degrees C). Furthermore, some BEN-carburized samples were further deposited by normal diamond growth conditions to form the ultra-sharp DLC-clad Si FEAs with enhanced emission ability.
Impact of interface nature on deep sub-micron Al-plug resistance
(2001-11-01)
Tsui, BY
;
Yang, TJ
;
Ku, TK
;
電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Sputter clean had been accepted as an effective surface clean process prior to metal deposition. In this work, the impact of interface nature on via resistance of Al-interconnect as via size is scaled down to 0.16 mum was studied. Al-F compound was identified as the main interfacial contaminants after standard post-etch clean process if the TiN laver of the underlying metal line were etched through during via etch. For via size larger than 0.25 mum (aspect ratio lower than 3.2), Al-F compound can be removed by sputter clean effectively. However, below 0.25 mum, sputter clean efficiency decreases such that via resistance is degraded by the existence of Al-F interfacial layer. On the other hand, sputter clean results in oxide re-deposition, which in turn degrades via resistance. It is suggested that to obtain low resistance sub-0.2 mum via, via etch must stop on TiN layer such that no Al-F layer can be formed. Otherwise, new interfacial layer clean technology with high efficiency and without side effect has to be developed. (C) 2001 Elsevier Science Ltd. All rights reserved.