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Title: In situ growth rate measurement of selective LPCVD of tungsten

Abstract

This paper reports on the reflectance measurement during the selective deposition of W on Si covered with an insulator rating proven to be a convenient method to monitor the W deposition. The reflectance change during deposition allows the in situ measurement of the deposition rate. The influence of surface roughening due to either the W growth or an etching pretreatment of the wafer is modeled, as well as the effect of selectivity loss and lateral overgrowth.

Authors:
; ;  [1]
+ Show Author Affiliations
  1. (Dept. of Electrochemistry, Univ. of Twente, 7500 AE Enshede (NL))
Publication Date:
OSTI Identifier:
5099159
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the Electrochemical Society; (United States); Journal Volume: 138:4
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; SILICON; FABRICATION; TUNGSTEN; CHEMICAL VAPOR DEPOSITION; ELECTRICAL INSULATORS; ETCHING; MATHEMATICAL MODELS; MEASURING METHODS; REFLECTION; CHEMICAL COATING; DEPOSITION; ELECTRICAL EQUIPMENT; ELEMENTS; EQUIPMENT; METALS; SEMIMETALS; SURFACE COATING; SURFACE FINISHING; TRANSITION ELEMENTS; 360101* - Metals & Alloys- Preparation & Fabrication; 360601 - Other Materials- Preparation & Manufacture

Citation Formats

Holleman, J., Hasper, A., and Middelhoek, J. In situ growth rate measurement of selective LPCVD of tungsten. United States: N. p., 1991. Web. doi:10.1149/1.2085758.
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Holleman, J., Hasper, A., & Middelhoek, J. In situ growth rate measurement of selective LPCVD of tungsten. United States. doi:10.1149/1.2085758.
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Holleman, J., Hasper, A., and Middelhoek, J. Mon . "In situ growth rate measurement of selective LPCVD of tungsten". United States. doi:10.1149/1.2085758.
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@article{osti_5099159,
title = {In situ growth rate measurement of selective LPCVD of tungsten},
author = {Holleman, J. and Hasper, A. and Middelhoek, J.},
abstractNote = {This paper reports on the reflectance measurement during the selective deposition of W on Si covered with an insulator rating proven to be a convenient method to monitor the W deposition. The reflectance change during deposition allows the in situ measurement of the deposition rate. The influence of surface roughening due to either the W growth or an etching pretreatment of the wafer is modeled, as well as the effect of selectivity loss and lateral overgrowth.},
doi = {10.1149/1.2085758},
journal = {Journal of the Electrochemical Society; (United States)},
number = ,
volume = 138:4,
place = {United States},
year = {Mon Apr 01 00:00:00 EST 1991},
month = {Mon Apr 01 00:00:00 EST 1991}
}
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Journal Article:
DOI:  10.1149/1.2085758
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  • ; - J. Electrochem. Soc.; (United States)
    Tungsten films have been deposited selectively on oxide-patterned silicon wafers by the H/sub 2/ reduction of WF/sub 6/ in WF/sub 6//sup -/H/sub 2/ and WF/sub 6//sup -/H/sub 2//sup -/Ar gas flow systems. The deposition rate of films was investigated a a function of reactant partial pressures. The reaction orders with respect to WF/sub 6/ and H/sub 2/ are zero and one-half, respectively. Under given experimental conditions, the growth rate of the selectively deposited W films was reduced by 32% when the deposition area increased by a factor of 10-100. This decrease in growth rate can be attributed to the effectmore » of HF on the surface reaction. The selective nature of the process deteriorates with increasing deposition rate, WF/sub 6/ partial pressure, H/sub 2/ partial pressure, or deposition time. The loss of selectivity seems to be linked to an increase in HF partial pressure in the reactor.« less

  • ; ; ; ... - J. Electrochem. Soc.; (United States)
    This study assesses the use of selective LPCVD tungsten as a contact barrier in VLSI circuits. Measurements of the contact resistance and leakage current are evaluated as a function of variations in W deposition parameters, implant type, implant dosage, and metallization heat-treatment. Addition of SiF/sub 4/ to alter the equilibrium of the displacement reaction is seen to cause minimal erosion and encroachment of the Si contacts as well as produce low and thermally stable contact resistance to both n/sup +/ and p/sup +/ diffusions. For surface doping concentrations of 1.44 x 10/sup 20/ cm/sup -3/ As and 0.62 x 10/supmore » 20/ cm/sup -3/B, measured values for the contact resistance for 2.0 ..mu..m sized vias are near 30..cap omega... Such values are quite compatible with high performance CMOS device requirements. Further reductions in these values are achieved with use of a self-aligned PtSi/W contact barrier metallization. The contact resistance for 2.0 ..mu..m sized vias are, in this case, near 4 and 15..cap omega.. for the n/sup +/ and p/sup +/ diffusions, respectively. Sporadic leakage across shallow n/sup +//P-Tub junctions remains, however, a serious problem associated with this selective LPCVD W process. Understanding the origin of this leakage and eliminating it can lead to numerous applications of this technology in VLSI manufacturing.« less

  • ; ; ; ... - J. Electrochem. Soc.; (United States)
    Molybdenum films have been deposited by low pressure chemical vapor deposition (LPCVD) on silicon substrates by the reduction of molybdenum hexafluoride in hydrogen and argon atmospheres. The deposition is extremely selective, with no Mo observed on silicon dioxide surfaces over the temperature range of 200/sup 0/-400/sup 0/C. Reduction by both hydrogen and silicon contribute to the deposition, with approximately equal, extremely high deposition rates; no self-limiting thickness was observed. Extensive TEM and SEM studies were conducted in order to characterize the microstructure of the deposited films. The main feature of the films is their extreme porosity - about 30%, whichmore » can explain many unusual properties of the process and the films. On the basis of experiments the authors propose a model to explain the origin of the porosity in the films. Comparative studies of tungsten and molybdenum LPCVD reveal that the difference between the two processes lie in the self-limiting mechanism occurring during the silicon reduction of tungsten hexafluoride.« less

  • ; ; ; ... - Journal of the Electrochemical Society; (United States)
    In this paper a model is presented to calculate the step coverage of blanket tungsten low pressure chemical vapor deposition (W-LPCVD) from tungsten hexafluoride (WF{sub 6}). The model can calculate tungsten growth in trenches and circular contact holes, in the case of the WF{sub 6} reduction by H{sub 2}, SiH{sub 4}, or both. The step coverage model predictions have been verified experimentally by scanning electron microscopy (SEM). The authors found that the predictions of the step coverage model for the H{sub 2} reduction of WF{sub 6} are very accurate, if the partial pressures of the reactants at the inlet ofmore » the trench or contact hole are known. To get these reactant inlet partial pressures, the authors used a reactor model which calculates the surface partial pressures of all the reactants. These calculated surface partial pressures are used as input for the authors' step coverage model. In this study the authors showed that thermodiffusion plays a very important role in the actual surface partial pressure. In the case where SiH{sub 4} was present in the gas mixture trends are predicted very well but the absolute values predicted by the step coverage model are too high. The partial pressure of HF, which is a by-product of the H{sub 2} reduction reaction, may be very high inside trenches or contact holes, especially just before closing of the trench or contact hole. The authors found no influence of the calculated HF partial pressure on the step coverage.« less

  • - Journal of the Electrochemical Society; (USA)
    Chemical vapor deposition has been used to deposit titanium nitride (TiN) on silicon wafers at low pressures in a cold-wall single-wafer reactor. Experiments are reported for pressures in the range of 100-300 mtorr and temperatures between 450{degrees}-700{degrees}C, with titanium tetrachloride and ammonia as reactants. Both hydrogen and nitrogen are evaluated as diluents. Deposition rates as high as 1000 {angstrom}/min have been achieved. The chemical nature of the films are evaluated by Auger and RBS techniques, while the morphology is depicted by SEM. For the most part, the films are stoichiometric and contain small quantities of oxygen, chlorine, and hydrogen.