Browsing by Author "WANG, PJ"

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AN EFFICIENT PRECLEAN OF ALUMINIZED SILICON SUBSTRATE FOR CHEMICAL-VAPOR-DEPOSITION OF SUBMICRON TUNGSTEN PLUGS
(1995-10-01)
YEH, WK
;
TSAI, MH
;
CHEN, SH
;
CHEN, MC
;
WANG, PJ
Preclean of aluminum trench and via patterned substrates is vital for successful selective chemical vapor deposition of tungsten (CVD-W). A convenient preclean method uses in situ. BCl3 plasma etching to remove the native metal oxide prior to conducting the CVD-W. During the plasma etching, however, the outsputtered aluminum oxide and aluminum can be redeposited on the sidewall of the trench and via hole and on the surface of the dielectric layer, where W nucleation is induced, resulting in creep-up and selectivity loss during tungsten deposition. By using a solution of hydroxylamine sulfate to pretreat the aluminum trench and via hole patterned substrates, we successfully avoid the creep-up and selectivity loss of W deposition.
AN EFFICIENT PRECLEAN OF ALUMINIZED SILICON SUBSTRATE FOR CHEMICAL-VAPOR-DEPOSITION OF SUBMICRON TUNGSTEN PLUGS
(1995-10-01)
YEH, WK
;
TSAI, MH
;
CHEN, SH
;
CHEN, MC
;
WANG, PJ
Preclean of aluminum trench and via patterned substrates is vital for successful selective chemical vapor deposition of tungsten (CVD-W). A convenient preclean method uses in situ. BCl3 plasma etching to remove the native metal oxide prior to conducting the CVD-W. During the plasma etching, however, the outsputtered aluminum oxide and aluminum can be redeposited on the sidewall of the trench and via hole and on the surface of the dielectric layer, where W nucleation is induced, resulting in creep-up and selectivity loss during tungsten deposition. By using a solution of hydroxylamine sulfate to pretreat the aluminum trench and via hole patterned substrates, we successfully avoid the creep-up and selectivity loss of W deposition.
ANOMALOUS DOPING BEHAVIOR OF IN-SITU BORON-DOPED POLYCRYSTALLINE SILICON DEPOSITED BY ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION
(1993-09-13)
LIN, HC
;
LIN, HY
;
CHANG, CY
;
LEI, TF
;
WANG, PJ
The deposition of in situ heavily boron-doped polycrystalline silicon (poly-Si) films was studied using an ultrahigh vacuum/chemical vapor deposition system. Fully activated carrier concentrations up to 3X10(20) cm-3 were obtained for the as-deposited films grown at 550-degrees-C. For boron concentration beyond this level, the crystallinity of poly-Si films degraded with increasing boron concentration, which resulted in an anomalous rise in resistivity. This crystallinity degradation occurred at a higher rate for films grown on a SiO2 surface than those grown on an undoped poly-Si surface. It is attributed to the preferential adsorption of boron atoms on the SiO2 surface. Under a high B2H6 flux condition, a large amount of boron atoms would accumulate on the SiO2 Surface before the formation of Si nuclei, and thus disturbs the subsequent film deposition and grain growth processes.
CHARACTERIZATION OF SI/SIGE STRAINED-LAYER SUPERLATTICES GROWN BY AN ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION TECHNIQUE
(1994-04-01)
CHANG, TC
;
CHANG, CY
;
JUNG, TG
;
TSAI, WC
;
HUANG, GW
High-resolution double-crystal X-ray diffraction and cross-sectional transmission electron microscopy were used to characterize the Si/SiGe strained-layer superlattices grown by the ultrahigh vacuum/chemical vapor deposition (UHV/CVD) system. A dynamical X-ray simulation was employed to analyze the experimental rocking curves. Good matches between the experimental rocking curves and the simulated ones demonstrate that the high quality Si/SiGe strained-layer superlattices with abrupt interface and excellent thickness and composition uniformity have been achieved. Thickness uniformity was further confirmed by the cross-sectional transmission electron microscopy. In addition, high-resolution double-crystal X-ray diffraction was proven to be a powerful technique for determining the doping level and the thickness of heavily doped contact layer in Si/SiGe device structures prior to further processing. Good wafer-to-wafer uniformity can be simultaneously achieved by the UHV/CVD technique; as a result, the UHV/CVD technique is readily applicable to manufacturing.
DEPOSITION OF IN-SITU BORON-DOPED POLYCRYSTALLINE SILICON FILMS AT REDUCED PRESSURES
(1994-02-07)
LIN, HC
;
LIN, HY
;
CHANG, CY
;
LEI, TF
;
WANG, PJ
We report on the deposition of in situ boron-doped polycrystalline Si films on the SiO2 surface with reduced growth pressures at 550 degrees C. The deposition rate of these films decreased as the doping level was greater than 10(19) cm(-3). Such a result is in sharp contrast to what has been observed previously for similar films grown with conventional low pressure chemical vapor deposition techniques. It was also found that the incubation time prior to the deposition of these films diminished as the doping level was increased to 3x10(20) cm(-3) or higher. It is attributed to the preferential adsorption of boron atoms on the SiO2 surface at the initial stage of growth, which facilitates the nucleation of Si.
EFFECT OF BORON DOPING ON THE STRUCTURAL-PROPERTIES OF POLYCRYSTALLINE SILICON FILMS GROWN AT REDUCED PRESSURES
(1994-08-01)
LIN, HC
;
LIN, HY
;
CHANG, CY
;
JUNG, TG
;
WANG, PJ
The deposition and properties of in situ boron-doped polycrystalline silicon (poly-Si) films grown at 550-degrees-C were investigated using an ultrahigh vacuum chemical vapor deposition system. It is observed that, if the doping level is high enough, the boron incorporation would significantly reduce the deposition rate, impede the grain growth, and degrade the crystallinity of the poly-Si films. We also found that the preferential adsorption of boron atoms on the SiO2 surface at the initial stage of deposition shortened the incubation time of deposition. The property of trapping states at the grain boundary is also examined, and a density of about 4.7 X 10(12) CM-2 is obtained for poly-Si films with a doping level less than 2.2 X 10(19) cm-3.
ENHANCEMENT OF BAND-EDGE LUMINESCENCE IN HYDROGENATED STRAINED SI(0.84)GE(0.16)/SI QUANTUM-WELLS BY PHOTOCHEMICAL VAPOR-DEPOSITION
(1993-12-01)
PAN, SC
;
CHEN, YF
;
CHANG, DC
;
CHANG, CY
;
WANG, PJ
Well-resolved band-edge luminescence spectra are reported for strained Si0.84Ge0.16/Si quantum wells grown by ultrahigh-vacuum chemical-vapor-deposition at 550-degrees-C. Phonon assisted transitions are also observed and the phonon structure of the spectrum is resolved. Blue shifting of the peak emission with decreasing well width is found in good agreement with theoretical calculations. The effects of hydrogenation using photochemical vapor deposition system are studied and an enhancement of the band edge luminescence intensity by a factor of three accompanied with a decrease in the intensity of the peaks coming from lattice defects is observed after hydrogenation. These results indicate that photochemical vapor deposition system is a useful tool for injecting atomic hydrogen into Si1-xGex/Si quantum wells and to enhance the band edge luminescence as well as to passivate the activity of the defects.
GROWTH OF UNDOPED POLYCRYSTALLINE SI BY AN ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION SYSTEM
(1993-09-06)
LIN, HC
;
LIN, HY
;
CHANG, CY
;
LEI, TF
;
WANG, PJ
Deposition of undoped polycrystalline-silicon (poly-Si) films on SiO2 using an ultrahigh vacuum chemical vapor deposition system was investigated. Poly-Si films with high crystallinity were obtained at a temperature as low as 525-degrees-C. The layer growth process was found to proceed with an activation energy of 44 +/- 2 kcal/mol, and is dominated by the desorption rate of surface-bonded hydrogen atoms. An incubation time was observed prior to the film deposition. This incubation period increased with decreasing growth temperature, resulting from slower nucleation and growth rates ai lower temperatures.
LOW-TEMPERATURE EPITAXIAL-GROWTH OF SILICON AND SILICON-GERMANIUM ALLOY BY ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION
(1994-01-01)
JUNG, TG
;
CHANG, CY
;
CHANG, TC
;
LIN, HC
;
WANG, T
Low-temperature epitaxy of silicon and silicon-germanium alloy via an ultrahigh-vacuum chemical vapor deposition system was investigated. Bistable conditions were observed for silicon epitaxial growth performed within the temperature range of 550 degrees C to 800 degrees C. The activation energy of the SiGe growth rate was found to decrease as the germanium composition increased. The germanium atomic molar fraction in these epitaxial layers was tightly controlled by a computer-controlled gas source switching system. Si/SiGe superlattice structures of 20-period 5 nm Si/12 nm SiGe layers were grown to demonstrate the excellent controllability of this growth technique.
NANOMETER THICK SI/SIGE STRAINED-LAYER SUPERLATTICES GROWN BY AN ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION TECHNIQUE
(1994-04-01)
CHANG, TC
;
CHANG, CY
;
JUNG, TG
;
TSAI, WC
;
WANG, PJ
High quality Si/Si1-xGex superlattices having layers as thin as 1.5 nm have been grown by an ultrahigh vacuum/chemical vapor deposition system. High-resolution double-crystal x-ray diffraction, and conventional and high-resolution cross-sectional transmission electron microscopy were used to evaluate the crystalline quality of these superlattices. A dynamical x-ray simulation program was employed to analyze the experimental rocking curves. Excellent matches between experimental rocking curves and simulated ones were obtained for all superlattices with various periodicity. A cross-sectional transmission electron micrograph of an 80 period Si(4.2 nm)/Si0.878Ge0.122 (1.5 nm) superlattice, in which each individual layers was clearly resolved, demonstrated the capability of this growth technique for nanometer thick layer deposition.
OBSERVATION OF QUANTUM CONFINEMENT EFFECTS IN STRAINED SI0.84GE0.16/SI QUANTUM-WELLS AT ROOM-TEMPERATURE
(1993-05-24)
CHEN, YF
;
DAI, YT
;
CHOU, HP
;
CHANG, DC
;
CHANG, CY
We report the first study of quantum confinement shifts of energy gap in strained Si0.84Ge0.16/Si quantum wells at room temperature by photothermal deflection spectroscopy (PDS) technique. The experimental results obtained from the amplitude and phase of the PDS signal are in good agreement with quantum well subband calculation.
QUANTUM CONFINEMENT EFFECTS OF SI/SIGE STRAINED-LAYER SUPERLATTICES GROWN BY AN ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION TECHNIQUE
(1994-12-01)
CHANG, TC
;
CHANG, CY
;
JUNG, TG
;
CHEN, PA
;
TSAI, WC
Well-resolved band-edge luminescence is observed for Si0.86Ge0.14/Si strained-layer superlattices grown by an ultrahigh vacuum/chemical vapour deposition technique at 550 degrees C. High-resolution double-crystal X-ray diffraction (HRXRD) and cross-sectional transmission electron microscopy (XTEM) were used to determine the strain and other parameters for these strained-layer superlattices. Quantum confinement is observed for a SiGe well as thin as 1.3 nm. The blue shift of the emission peaks with decreasing well width is found to be in good agreement with theoretical calculation.
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).