Browsing by Author "Liu, LM"

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Deposition properties of selective tungsten chemical vapor deposition
(1996-09-01)
Yeh, WK
;
Chen, MC
;
Wang, PJ
;
Liu, LM
;
Lin, MS
This work investigates the basic deposition properties of selective tungsten chemical vapor deposition (W-CVD) using the process of silane reduction of WF6 with the SiH4/WF6 flow rate ratio less than 0.6 over the temperature range 280-350 degrees C. Selective W-CVD was performed on a contact hole patterned silicon substrate with in situ NF3 plasma etching of the silicon substrate prior to the selective tungsten deposition. The W deposition rate, deposition selectivity and W film resistivity were investigated with respect to the SiH4 partial pressure, WF6 partial pressure, total (SiH4 + WF6) deposition pressure, as well as the flow rate of the hydrogen carrier gas. It was found that the deposition rate is proportional to the SiH4 partial pressure, With a constant SiH4/WF6 flow rate ratio, the deposition rate increases with total pressure. At given flow rates of SiH4 and WF6, the deposition rate and film resistivity are dependent on the flow rate of the carrier gas. The experimental results show that the reverse bias junction leakage for the wet etching pretreated W/p(+)-n junction diode is smaller than that of the plasma pretreated diode. On the other hand, the contact resistance of the Al/W/n(+)p diode is smaller than that of the Al/W/p(+)n diode.
Enhanced metalorganic chemical vapor deposition titanium nitride film fabricated using tetrakis-dimethylamino-titanium for barrier metal application in sub-half-micron technology
(1996-08-01)
Wang, CK
;
Liu, LM
;
Liao, M
;
Cheng, HC
;
Lin, MS
Enhanced metalorganic chemical vapor deposition (MOCVD) titanium nitride (TiN:C) film with low resistivity (< 700 mu Omega . cm) has been fabricated by thermal decomposition of tetrakis-dimethylamino-titanium (TDMAT; Ti[N(CH3)(2)](4)) Enhancement is carried out by in-situ N-2 plasma treatment of as-deposited TiN:C film and the enhanced TiN:C film has good stability: less than 4% increase in film resistivity after exposure to air for 24 days. The amount of oxygen absorbed in this enhanced TiN:C film after air exposure, determined by Auger electron spectroscopy (AES) was significantly reduced. This enhanced MOCVD TiN:C film has been successfully applied to sub-half-micron devices. A void-tree tungsten plug (W plug) for sub-half-micron holes can be achieved. Good barrier performance and low contact/via resistance have also been demonstrated.
Enhanced metalorganic chemical vapor deposition titanium nitride film fabricated using tetrakis-dimethylamino-titanium for barrier metal application in sub-half-micron technology
(1996-08-01)
Wang, CK
;
Liu, LM
;
Liao, M
;
Cheng, HC
;
Lin, MS
Enhanced metalorganic chemical vapor deposition (MOCVD) titanium nitride (TiN:C) film with low resistivity (< 700 mu Omega . cm) has been fabricated by thermal decomposition of tetrakis-dimethylamino-titanium (TDMAT; Ti[N(CH3)(2)](4)) Enhancement is carried out by in-situ N-2 plasma treatment of as-deposited TiN:C film and the enhanced TiN:C film has good stability: less than 4% increase in film resistivity after exposure to air for 24 days. The amount of oxygen absorbed in this enhanced TiN:C film after air exposure, determined by Auger electron spectroscopy (AES) was significantly reduced. This enhanced MOCVD TiN:C film has been successfully applied to sub-half-micron devices. A void-tree tungsten plug (W plug) for sub-half-micron holes can be achieved. Good barrier performance and low contact/via resistance have also been demonstrated.
Optimization of PVD Ti/CVD TiN liner for 0.35 mu m tungsten plug technology
(1996)
Wang, CK
;
Liu, LM
;
Liao, DM
;
Smith, DC
;
Danek, M
A novel plasma enhanced CVD TiN process was integrated with high density plasma sputter etch preclean (PCII) and 1:1.5 collimated PVD Ti (c-PVD Ti) process to deposit a Ti/TiN liner for tungsten contact and via plugs. The integrated liner process was optimized for a 0.35 mu m non-salicide CMOS device application. RF power and sputter depth used for contact preclean were the major process Variants affecting the contact resistance, junction leakage and transistor threshold voltage. Low contact resistance was obtained for a c-PVD Ti thickness of similar to 375 Angstrom. Via resistance was significantly lower with c-PVD Ti/CVD TiN liner as compared to only a TiN liner. Contact resistance for c-PVD Ti/c-PVD TIN and c-PVD Ti/CVD TiN liners were comparable while contacts with conventional PVD Ti/TiN liner showed significantly higher values due to poor step coverage. Low junction leakage current was obtained for integrated c-PVD Ti/CVD TiN stack.
Selective tungsten CVD on submicron contact hole
(1995-12-01)
Yeh, WK
;
Chen, MC
;
Wang, PJ
;
Liu, LM
;
Lin, MS
This work investigates the deposition properties of selective chemically vapor-deposited tungsten for filling the deep sub-half micron contact holes using the process of silane reduction of tungsten hexafluoride. Low-resistivity tungsten with excellent selectivity and conformal coverage can be obtained with a SiH4/WF6 flow rate ratios less than 0.6 at deposition temperatures between 280 to 350 degrees C. Junction leakage and contact resistance of the AlSiCu/W/n(+)p and AlSiCu/W/p(+)n diodes as well as the electromigration properties of the AlSiCu/W/n(+)p structure were investigated.
Thermal stability of AlSiCu/W/n(+)p diodes with and without TiN barrier layer
(1995-12-01)
Yeh, WK
;
Chen, MC
;
Wang, PJ
;
Liu, LM
;
Lin, MS
Thermal stability of AlSiCu/W/n(+)p diodes with two different W contact structures prepared by selective W chemical vapour deposition (W-CVD), was first investigated. The diodes with the self-aligned W-contacted structure were able to sustain a 30 min furnace annealing up to 500 degrees C without degradation of electrical characteristics. The diodes with the contact-hole W-contacted structure were thermally less stable than the diodes with the self-aligned W-contacted structure, presumably because the sidewall of the W-filled contact hole provided a path for diffusion of Al into the Si substrate, leading to junction spiking. The insertion of a 400 Angstrom TiN barrier layer between the AlSiCu and W films blocked the Al diffusion path; thus, the AlSiCu/TiN/W/n(+)p diode was able to retain its integrity up to 550 degrees C furnace annealing.