Browsing by Author "CHAO, TS"

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A NOVEL PLANARIZATION OF TRENCH ISOLATION USING POLYSILICON REFILL AND ETCHBACK OF CHEMICAL-MECHANICAL POLISH
(1995-10-01)
CHENG, JY
;
LEI, TF
;
CHAO, TS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The planarization of trench isolation refilled by deposition oi polysilicon was investigated. Results show that the planarization by RIE etching has poor surface planarity. On the other hand, an excellent surface planarity can be achieved by the CMP process resulting from the high etching selectivity of polysilicon to nitride. This simple process provides a very promising candidate for trench isolation.
A NOVEL PLANARIZATION OF TRENCH ISOLATION USING POLYSILICON REFILL AND ETCHBACK OF CHEMICAL-MECHANICAL POLISH
(1995-10-01)
CHENG, JY
;
LEI, TF
;
CHAO, TS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The planarization of trench isolation refilled by deposition oi polysilicon was investigated. Results show that the planarization by RIE etching has poor surface planarity. On the other hand, an excellent surface planarity can be achieved by the CMP process resulting from the high etching selectivity of polysilicon to nitride. This simple process provides a very promising candidate for trench isolation.
A STUDY OF THE INTERFACIAL LAYER OF AL AND AL(1-PERCENT SI)-SI CONTACTS USING A ZERO-LAYER ELLIPSOMETRY MODEL
(1992-11-01)
CHAO, TS
;
LEE, CL
;
LEI, TF
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this work, the interfacial layer of the Al-Si and Al(1% Si) Si contacting system annealed at different temperatures have been studied using ellipsometry incorporated with a zero-layer model. The results show that the thickness of the interfacial P+ layer between Al or Al(1% Si) and the Si-substrate increases with the annealing temperature and the thickness of the P+-layer of the Al(1% Si)-Si system is generally lower than that of the Al-Si system. Also, the fraction of Al in the interfacial layer decreases with the annealing temperature for the Al-Si system, but increases for the Al(1% Si)-Si system. The electrical measurements show that the interface of the Al(1% Si)-Si contact is more stable than that of the Al-Si contact.
CHARACTERIZATION OF SEMIINSULATING POLYCRYSTALLINE SILICON PREPARED BY LOW-PRESSURE CHEMICAL-VAPOR-DEPOSITION
(1993-09-01)
CHAO, TS
;
LEE, CL
;
LEI, TF
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We employed the multiple angle incident ellipsometer to study the growth mechanism and optical properties of semi-insulating polycrystalline silicon (SIPOS) films deposited by the low-pressure chemical vapor deposition (LPCVD) technique. A significant difference of the imaginary part of the refractive index between film at the edge and those in the central region of the wafer was observed. Our analyses showed that it was consistent with the N2O depletion model. This N2O depletion phenomenon was confirmed by Auger analysis. Moreover, we found that spatial N2O depletion at the edge of the wafer was greatly influenced by the flow rate of SiH4 to N2O gases. Excessively high N2O flow rate suppressed the silicon microcrystal resulting in a thinner SIPOS film.
CHARACTERIZATIONS OF OXIDE GROWN BY N2O
(1993-10-01)
CHAO, TS
;
CHEN, WH
;
SUN, SC
;
CHANG, HY
;
電控工程研究所
The constitution of N2O oxide has been investigated by using Auger analyses, ellipsometry measurement, and Fourier transform infrared (FTIR) spectroscopy in this paper. We found a nitrogen-rich layer formed at the interface of SiO2/Si by Auger analyses. From the results of ellipsometry, we found the thinner the N2O oxide, the larger the refractive index. A two-layer model construction of N2O oxide was proposed for modeling the interfacial layer. We found that this layer thickness is 14 to 20 angstrom when the refractive index was set to 1.77. FTIR analyses show that some of the Si-O bonds were replaced by Si-N bonds. This is the reason that N2O oxide has better electrical properties and a lower growth rate than those of the conventional dry 02 oxide.
CROSSOVER PHENOMENON IN OXIDATION RATES OF THE (110) AND (111) ORIENTATIONS OF SILICON IN N2O
(1995-03-01)
CHAO, TS
;
LEI, TF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Growth mechanisms of three different orientations Si wafer oxidized in N2O have been investigated in this study. A thickness crossover phenomenon in oxidation rates was found for orientations (110) and (111) at a critical oxide thickness 150 Angstrom. From our results, this phenomenon is closely related with the initial native oxide before oxidation.
EFFECTS OF POSTETCHING TREATMENTS ON ELECTRICAL CHARACTERISTICS OF THERMAL OXIDES ON REACTIVE-ION-ETCHED SILICON SUBSTRATES
(1995-09-01)
CHENG, HC
;
UENG, SY
;
WANG, PW
;
KANG, TK
;
CHAO, TS
Thin oxides thermally grown on the reactive-ion-etched (RIE) silicon substrates in N2O and diluted O-2 ambients have been studied. The RIE will strongly affect the silicon surface microroughness and lead to poor oxides properties. Using the after-treatment-chamber (ATC) process, CF4 addition in the O-2 plasma can further improve the time-zero-to-dielectric-breakdown (TZDB) characteristics of the thin oxides as compared with pure O-2 plasma. This is because CF4 addition in the ATC can remove the damaged silicon layer and smooth the silicon surface since the (O)2 plasma can effectively only strip the polymeric layer. In addition, the N2O-grown oxides can enlarge the process window of the CF4/O-2 ATC treatments with respect to pure oxides.
ELLIPSOMETRIC MEASUREMENTS AND ITS ALIGNMENT - USING THE INTENSITY RATIO TECHNIQUE
(1995-09-01)
CHAO, YF
;
WEI, CS
;
LEE, WC
;
LIN, SC
;
CHAO, TS
Using first-order treatment on azimuth errors of the polarizer (P) and analyzer (A) with respect to the plane of incidence (POI), we construct two intensity ratios around a certain configuration: such as P = +/- pi/4 and A = 0 as compared to A = pi/2. These expressions can be used not only to align the azimuths of the polarizer and analyzer to the POI, hut also to obtain the ellipsometric parameter phi without locating the minimum intensity, BK7 glass and SiO2/Si thin film are ultilized to evaluate this technique.
ELLIPSOMETRY MEASUREMENT OF THE COMPLEX REFRACTIVE-INDEX AND THICKNESS OF POLYSILICON THIN-FILMS
(1990-02-01)
HO, JH
;
LEE, CL
;
LEI, TF
;
CHAO, TS
;
交大名義發表
FOURIER-TRANSFORM INFRARED SPECTROSCOPIC STUDY OF OXIDE-FILMS GROWN IN PURE N2O
(1995-05-01)
CHAO, TS
;
CHEN, WH
;
LEI, TF
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The properties of the oxide films grown by pure N2O were studied in this work. A two-layer model, considering a N2O oxide with an oxy-nitride film at the interface, was used to describe the dependence of the main peak shift in a Fourier transform infrared (FTIR) spectrum on N2O thicknesses. The thickness of interfacial layer was determined by FTIR and multiple-angle incident ellipsometer. Both methods showed consistent results and the thickness of this layer is found to be 14-16 Angstrom.
IMPROVEMENT OF THIN OXIDES THERMALLY GROWN ON THE REACTIVE-ION-ETCHED SILICON SUBSTRATES
(1995-05-01)
UENG, SY
;
WANG, PW
;
KANG, TK
;
CHAO, TS
;
CHEN, WH
Thin oxides thermally grown in reactive-ion-etched (RIE) silicon substrates in N2O and diluted O-2 ambient have been studied. The microroughness of the oxide-silicon interface was investigated using a spectrophotometer, atomic force microscopy (AFM), and cross-sectional high-resolution electron microscopy (HRTEM). The microroughness is strongly dependent on the RIE conditions and the post etching treatments. Furthermore, oxidation-enhanced interface microroughness has been observed. As compared with the pure oxides grown in diluted oxygen, N2O-grown oxides exhibit stronger immunity to RIE-induced damage. N2O oxidation of the etched specimens treated with an after-treatment-chamber (ATC) process result in the best electrical properties.
INHIBITION OF BIRDS BEAK IN LOCOS BY NEW BUFFER N2O OXIDE
(1995-02-16)
CHAO, TS
;
CHENG, JY
;
LEI, TF
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In the Letter new N2O buffer oxide was used to replace the conventional dry oxide for LOGOS isolation. This new structure can result in a shorter bird's beak than the conventional structure without adding extra steps and inducing the defect in silicon substrate.
MEASUREMENT OF THIN OXIDE-FILMS ON IMPLANTED SI-SUBSTRATE BY ELLIPSOMETRY
(1994-04-01)
CHAO, TS
;
LEI, TF
;
CHANG, CY
;
LEE, CL
;
電子工程學系及電子研究所
In this study, the thickness of oxide film which is deposited by low-temperature chemical vapor deposition (LTCVD) on an implanted silicon substrate was measured by multiple-angle incident (MAI) ellipsometry. By using this method, the refractive index, thickness, and the effective index of the substrate can be calculated simultaneously. It is found that the thickness of oxide film on an implanted silicon substrate is only 4% different from that on a nonimplanted silicon substrate under the same deposition conditions. The result shows that a higher implantation energy results in a higher effective substrate index. Even with a high temperature and long annealing process, the refractive index of the implanted silicon substrate cannot recover to the value of nonimplanted silicon substrate.
MEASUREMENT OF ULTRATHIN (LESS-THAN-100-A) OXIDE-FILMS BY MULTIPLE-ANGLE INCIDENT ELLIPSOMETRY
(1991-06-01)
CHAO, TS
;
LEE, CL
;
LEI, TF
;
交大名義發表
;
電控工程研究所
The application of the multiple-angle incident ellipsometry to measure the ultrathin (< 100 angstrom) oxide has been studied in this paper. First, four interfacial models are investigated by using a fitting scheme to fit ellipsometric data (DELTA, psi) at various incident angles, and the abrupt model is found to be the most appropriate model to model the transition region of the SiO2-Si interface. The sensitivities on the incident angle and the errors induced by the ellipsometric parameter variations are also analyzed. Ellipsometry is applied to measure the native oxides of Si wafers after they are treated with different cleaning processes, and it is also applied to measure refractive indexes and thicknesses of ultrathin thermally grown SiO2. It is believed that these are the most accurately measured results on the refractive indexes of ultrathin oxides. Also, an empirical formula for thermal oxide growth in dry O2 is obtained.
MULTIPLE-ANGLE INCIDENT ELLIPSOMETRY MEASUREMENT ON LOW-PRESSURE CHEMICAL-VAPOR-DEPOSITED AMORPHOUS-SILICON AND POLYSILICON
(1994-08-01)
CHAO, TS
;
LEE, CL
;
LEI, TF
;
電子工程學系及電子研究所
;
奈米中心
Multiple-angle incident (MAI) ellipsometry is used to study the optical properties of both amorphous silicon and poly-Si after different heat-treatments. At first, the error sensitivity of MAI ellipsometry has been studied and the optimum conditions to achieve the best precision are obtained. The optical constants and thickness of amorphous silicon deposited by LPCVD at 550-degrees-C changed significantly after sample annealing. The optical constants of the amorphous silicon reached the values of single-crystalline silicon after annealing for both the high and low temperature treatments. A thickness shrinking phenomenon is observed when amorphous silicon is transformed to the polycrystalline form. This phenomenon is confirmed by cross-sectional TEM photography. The thickness shrinking ratio is 3.5 to 6.0%.
NITRIDATION OF THE STACKED POLY-SI GATE TO SUPPRESS THE BORON PENETRATION IN PMOS
(1995-06-01)
LIN, YH
;
LAI, SC
;
LEE, CL
;
LEI, TF
;
CHAO, TS
Nitridation to create nitrogen-rich layers in-between the stacked layers of the poly-Si gate to suppress the boron penetration for pMOS with the gate BF (+)(2)-implantation is proposed and demonstrated, The MOS capacitors fabricated by using this nitridized stacked poly-Si gate have better thermal stability and much improved electrical characteristics.
POLY-OXIDE POLY-SI/SIO2/SI STRUCTURE FOR ELLIPSOMETRY MEASUREMENT
(1992-06-04)
CHAO, TS
;
LEE, CL
;
LEI, TF
;
YEN, YT
;
電子工程學系及電子研究所
A multiple poly-oxide/poly-Si/SiO2/Si sandwiched structure is proposed for the conventional single incident angle and single wavelength ellipsometry measurement of the thicknesses and refractive indices of the poly-oxide and the poly-Si at the same time. The structure is simple and gives accurate results.
POST-POLYSILICON GATE-PROCESS-INDUCED DEGRADATION ON THIN GATE OXIDE
(1995-11-01)
LAI, CS
;
LEI, TF
;
LEE, CL
;
CHAO, TS
;
電子工程學系及電子研究所
The post-polysilicon gate-process-induced degradation on the underlying gate oxide is studied. The degradation includes an increase in the electron trapping rate and a decrease in the charge-to-breakdown, Q(bd), Of the gate oxide, It is found that N2O nitrided gate oxide is more robust than O-2 gate oxide in resisting the degradation, Also, to grow a thin polyoxide on the polysilicon-gate in N2O rather than in O-2 lessens the degradation on the underlying gate oxide, It is nitrogen, which diffuses through the polysilicon gate and piles up at both polysilicon/oxide and oxide/silicon-substrate interfaces, that improves the oxide quality for the N2O process.
SUPERIOR DAMAGE-IMMUNITY OF THIN OXIDES THERMALLY GROWN ON REACTIVE-ION-ETCHED SILICON SURFACE IN N2O AMBIENT
(1994-05-01)
UENG, SY
;
CHAO, TS
;
WANG, PJ
;
CHEN, WH
;
CHANG, DC
Thin oxides thermally grown on reactive-ion-etched silicon surfaces in N2O ambient have been studied. As compared with pure oxides grown on the etched silicon in dry oxygen, N2O-grown oxides exhibit significantly stronger immunity to the RIE-induced damages. A great improvement in both time-zero-dielectric-breakdown (TZDB) and time-dependent-breakdown (TDDB) characteristics is observed for the N2O-grown oxides on RIE-treated silicon surfaces. Accelerated tests have shown that the N2O oxide grown on the RIE silicon surface can achieve a lifetime longer than the pure oxide grown on the correspondingly etched silicon surface with a factor over 10(8).
SUPPRESSION OF BORON PENETRATION IN PMOS BY USING BRIDE GETTERING EFFECT IN POLY-SI GATE
(1995-02-01)
LIN, YH
;
LEE, CL
;
LEI, TF
;
CHAO, TS
;
電子工程學系及電子研究所
A new stacked poly-Si gate structure with a thin (similar to 20 Angstrom) oxide inserted in-between for p-channel metal-oxide semiconductor feild effect transistor (pMOSFET) application is proposed and demonstrated. Due to the gettering flourine effect of this thin oxide for BF2+-implanted poly-Si gate, the amount of fluorine in the gate oxide, consequently, the boron penetration enhanced by fluorine are reduced. The thicker or the more apart from the gate oxide of this gettering fluorine oxide is, the more effectively it can suppress the boron penetration. Moreover, this new structure improves more the electrical characteristics than the conventional and the stacked layer poly silicon gate structures.