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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]
  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.
Holleman, J., Hasper, A., & Middelhoek, J. In situ growth rate measurement of selective LPCVD of tungsten. United States. doi:10.1149/1.2085758.
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.
@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}
}
  • 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
  • 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
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