Browsing by Author "LIAUH, HR"

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ELECTRICAL AND MICROSTRUCTURAL CHARACTERISTICS OF TI CONTACTS ON (001)SI
(1993-08-15)
LIAUH, HR
;
CHEN, MC
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CHEN, JF
;
CHEN, LJ
;
電子工程學系及電子研究所
An investigation of the electrical and microstructural characteristics of the Ti contact on silicon has been carried out. The presence of As in Ti/n+-Si samples was found to retard the formation of polycrystalline silicide (p-silicide) compared with that in Ti/p+-Si samples with BF2+ implantation. Amorphous interlayers (a-interlayers) were found to be present in both Ti/n-Si and Ti/p-Si samples annealed at temperatures of and lower than 450-degrees-C. Although the Schottky barrier heights (SBH's) vary for about 0.05-0.08 eV for samples annealed over a temperature range from room temperature to 900-degrees-C, SBH's at the a-interlayer/n-Si and a-interlayer/p-Si were measured to be about 0.52-0.54 and 0.59-0.57 eV, respectively. The specific contact resistance (p(c)) in the Ti/n+-Si system was measured to be the lowest with a value of 1.4 X 10(-7) OMEGA cm2 when the a interlayer is present. In Ti/p+-Si system, the minimum rho(c) is about 3 X 10(-7) OMEGA cm2. The variation in contact resistance with annealing temperature for both Ti/n+-Si and Ti/p+-Si samples is correlated to the change in dopant concentration beneath the contacts as well as microstructures. In the temperature regime where the a interlayer is in contact with the silicon substrate, the junction diode leakage current densities (J(leak's)) are considerably lower than those in samples annealed at higher temperatures. The J(leak) at - 6 V reverse bias is lower than 1 nA/cm2. The breakdown voltage is about 14 V (16 V) for the n+/p (p+/n) junction. The thickness of consumed Si is less in samples annealed at low temperature, and the a-interlayer/Si or p-silicide/Si interface is accordingly farther away from the junction as well as the end-of-range defects. The interface of p-silicide/Si is rougher than that of a-interlayer/Si. In addition, the roughness of the p-silicide/Si interface increases with annealing temperature. For both p+/n and n+/p junctions annealed at 900-degrees-C, rough p-silicide/Si interfaces are thought to lead to spiking and increase the leakage currents.
INFLUENCE OF CONTACT TREATMENTS ON THE ELECTRICAL CHARACTERISTICS OF SHALLOW-JUNCTION TITANIUM-BASED CONTACTS
(1992-06-01)
LIAUH, HR
;
TSENG, MF
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CHEN, MC
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CHEN, LJ
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電子工程學系及電子研究所
A comparison of the electrical characteristics of Al-Si/TiW/TiSi2/Si, Al-Si/TiW/Ti/Si and Al-Si/Si contact structures has been carried out. The influence of a contact implantation and anneal on the electrical characteristics of the TiSi2 contacted shallow junctions has also been investigated. Compared with the Al-Si/TiW/TiSi2/Si contact system, the Al-Si/TiW/Ti/Si contact was shown to be a more suitable metalization scheme for the shallow junction contact technology, due to its lower contact resistance and junction leakage as well as its simplicity of fabrication process. The contact resistance of the Ti/n+-Si system was found to be lower than that of the TiSi2/n+-Si system. The low contact resistance of Ti/n+-Si is attributed to the presence of a uniform amorphous interlayer as well as significantly less influence of As on Ti/a-alloy/n+-Si compared to TiSi2/n+-Si. A contact anneal was found to reduce contact resistance for both TiSi2/n+-Si and TiSi2/p+-Si contact systems. With an additional P+ implantation and anneal, the contact resistances are drastically reduced for the n+-Si contacts. On the other hand, a B+ contact implantation and anneal did not significantly improve the contact performance of the TiSi2/p+-S system. The difference is thought to arise from the lower degree of recovery of B+ implantation damage resulted from the contact implantation of TiSi2/p+-Si contact compared to that of TiSi2/n+-Si contact. The addition of the contact P+ implantation increased the total dopant concentration underneath the surface to such an extent that it leads to a reduction in contact resistance.
INTERFACIAL REACTIONS OF TITANIUM THIN-FILMS ON ION-IMPLANTED (001) SI
(1993-04-01)
LIAUH, HR
;
CHEN, MC
;
CHEN, JF
;
CHEN, LJ
;
LUR, W
An investigation on the influences of doping impurities on the formation of titanium silicide has been carried out. The formation of polycrystalline silicide was observed to be retarded by the presence of As in Ti/As+-Si samples compared with those in Ti/BF2+-Si samples. Superior thermal stability of TiSi2 was found to occur in BF2+ implanted samples than that in blank and As+ implanted samples. The resistance to island formation in BF2+ implanted samples is attributed to the retardation of grain growth by the segregation of fluorine atoms at the grain boundaries.
SCHOTTKY-BARRIER HEIGHTS OF THE AMORPHOUS INTERLAYER SI INTERFACES IN TITANIUM THIN-FILMS ON (001)SI
(1992-11-02)
LIAUH, HR
;
CHEN, MC
;
CHEN, JF
;
CHEN, LJ
;
電子工程學系及電子研究所
Schottky barrier heights (SBHs) of amorphous interlayer/Si interfaces in Ti thin films on (001)Si have been measured by forward current-voltage technique. A-interlayers were observed to form by cross-sectional transmission electron microscopy in both Ti thin films on n- and p-type silicon systems in samples annealed at temperatures of and lower than 450-degrees-C for 30 s. Although the SBHs vary for about 0.05-0.08 eV for samples annealed over a temperature range from room temperature to 900-degrees-C, SBHs at the a-interlayer/n-Si and a-interlayer/p-Si were measured to be 0.52-0.54 and 0.59-0.57 eV, respectively. Formation of homogeneous metal a-interlayer/Si interfaces correlated with their SBHs in a number of refractory metal-silicon systems promises to greatly clarify the SBH formation mechanisms.