摘要:

Polycrystalline silicon–silicon dioxide–silicon capacitors were annealed in argon and argon containing oxygen ambients in a rapid thermal annealer. Capacitance–voltage (C–V) characteristics were determined before and after anneal as a function of annealing time at 1100 and 1200 °C.C–Vcharacteristics of the capacitors annealed in argon degraded with increased annealing time and temperature. At 1100 °C oxide capacitance decreased and oxide leakage occurred. At 1200 °C the annealing resulted in catastrophe, capacitance decreased by more than factor of ten. Careful examination of the thin oxide layer, after selective removal of the polysilicon film, showed holes in the oxide, hole density increasing with time and temperature. On the other hand,C–Vcharacteristics of capacitors, annealed in argon containing oxygen, had no significant change after anneal at 1100 °C. Also defect density was extremely low. TheC–Vcharacteristics of capacitors annealed in pure argon can be recovered by the anneal in oxygen ambient. Thermal oxide films on silicon wafers were annealed in argon at high temperatures. Formation and lateral growth of physical holes in the oxide layer was found. The linear relation between the size of hole and annealing time was verified. Results are discussed in terms of thermodynamic stability of silicon dioxide on silicon in inert and oxidizing mediums.

ISSN:1071-1023    

DOI:10.1116/1.584705

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Oxygen plasma treatments of thin cap layers of Ti, Ta, W, or W–10% Ti deposited over Al or refractory metal silicide films can significantly reduce the optical reflectivity. The reduction is proportional to the thickness of oxide film grown on the cap layer. The oxidation occurs mostly in the first 5 min of plasma treatment and is a function of temperature. The oxide films have been characterized by Auger spectroscopy, Rutherford backscattering spectrometry, and ellipsometry. The measured reflectivities agree very well with the calculated results. This reduction in reflectivity is useful for photoresist processing as demonstrated by both computer modeling and experimental photoresist linewidth measurement.

ISSN:1071-1023    

DOI:10.1116/1.584706

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Hydrogen concentration depth profiles in silicon nitride films deposited by low‐pressure chemical vapor deposition (LPCVD) and plasma enhanced chemical vapor deposition (PECVD) techniques were studied. Quantitative hydrogen profiling was carried out using the resonant nuclear reaction15N+1H→12C+4He+γ ray. Hydrogen concentration in as‐deposited LPCVD silicon nitride films was ∼2.5×1021atoms/cm3and was stable even after a furnace anneal at 450 °C in 3% H2/Ar for 30 min or a rapid thermal anneal at 1000 °C in oxygen for 30 s. These nitride films thus appear to be good hydrogen diffusion barriers. In contrast, hydrogen concentration in as‐deposited PECVD silicon nitride films was ∼1.75×1022atoms/cm3and dropped to ∼7.5×1021atoms/cm3after rapid thermal annealing at 1000 °C in oxygen for 30 s. During high‐temperature anneals, the hydrogen diffused from PECVD silicon nitride film into the underlying SiO2layer. A comparison of the hydrogen concentration in these deposited oxides under the nitrides with those previously reported for as‐deposited, but uncovered, SiO2films points out that the observed threshold voltage shifts in nitride covered metal–oxide semiconductor capacitors are related to the loss of hydrogen from the silicon oxide during vacuum processing for nitride deposition and to the subsequent diffusion in SiO2from the PECVD nitride films.

ISSN:1071-1023    

DOI:10.1116/1.584707

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

This paper presents studies of the infrared (IR) absorbance and the intrinsic stress in thermally grown very thin films (60 to 700 Å) of SiO2. These data are combined with previously obtained data for thicker thermally grown films (∼1300 Å) to study the variation in intrinsic growth stress close to the Si/SiO2interface. The combined data indicate that the intrinsic stress at Si/SiO2interfaces extrapolates to the same relatively high values for oxides grown at 700 and 1000 °C, and that the distribution of Si–O–Si bond angles close to the Si/SiO2interface, as deduced from the IR data, is quantitatively different than in the bulk of the oxide film. These two observations are explained in terms of a model based on a temperature dependent viscoelastic relaxation of the oxide stress. This model emphasizes differences in the thermal history of the SiO2near the Si/SiO2interface, as compared to the SiO2that is well removed from that interface and is in the bulk of the film and/or close to the ‘‘top’’ surface of the film. The observed differences between the 700 and 1000 °C bulk oxides, and the associated Si/SiO2interfaces are explained in terms of a renormalized time scale that is defined by the ratio of the growth time to the viscoelastic relaxation time at the growth temperature.

ISSN:1071-1023    

DOI:10.1116/1.584708

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

A two‐beam laser reflection technique was used to measure SiO2film stress during Si oxidation, i.e.,insituat the growth temperature. Results show a higher compressive intrinsic film stress near the Si–SiO2interface and a lower stress in the bulk of the SiO2film. Thermal stress is also measured by monitoring the SiO2film covered Si substrate curvature changes during temperature excursions. Our new results are in general agreement with previousexsitustress measurements and may indicate that film stress, being highest at the interface, influences the interface reaction in Si oxidation.

ISSN:1071-1023    

DOI:10.1116/1.584709

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Tungsten reactive ion etching formulations obtained from CF2Cl2in combination with CF4/O2, and from CF3Cl with O2, are known to exhibit distinct etch rate and etch selectivity advantages relative to other chemistries used for tungsten patterning. Within this work, it is found that CF3Cl in place of CF2Cl2causes a similar result and that it is the balanced presence of atomic F, Cl, and O in the discharge that governs the etch rate of tungsten. Limiting case approximations suggest that the mechanism of tungsten etch enhancement does not depend upon the potential for tungsten removal as a volatile chloride. The participation of tungsten oxide is also studied. Finally, the novel chemistries are extended to silicon etching, resulting in a similarly beneficial etch rate and selectivity advantage.

ISSN:1071-1023    

DOI:10.1116/1.584710

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

The oxygen plasma etching resistance of plasma polymerized organometalic film was measured. The films were deposited by downstream plasma deposition using gaseous mixtures of an organic monomer (C3H6) and a metal‐containing monomer tetramethyltin or tetramethylsilane. By changing the flow‐rate ratio of both monomers, the metal content of the film was reproducibly varied from 0% to 27%. It was found that the O2reactive ion etching rate depended on metal content in polymer, discharge power density, and oxygen gas pressure. High oxygen plasma etching resistance was obtained for films which contained even a few percent of metal. From the results of electron spectroscopy for chemical analysis and Auger electron spectroscopy measurements, it was observed that the metal‐oxidized layer was formed on the surface during oxygen plasma etching.

ISSN:1071-1023    

DOI:10.1116/1.584711

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

A secondary ion mass spectrometer (SIMS) has been added to a liquid metal source instrument which was designed as a micromachining apparatus. The SIMS performance rivals any reports to date on similar devices, even though no compromises were made with the primary function of the apparatus. End‐point detection for ion milling allows depth control within a few hundred angstroms, on micron sized raster fields. A sensitivity of 4×10 5cps/nA is routinely measured on52Cr+signals; similar count rates are also obtained from Al. Ion images on Cr or Al with sub‐micron resolution with a 25‐μm field are obtained in as little as 10 s collection time. Features as small as 0.3 μm can be defined by the secondary ion imaging, with the removal of only a few monolayers of material.

ISSN:1071-1023    

DOI:10.1116/1.584712

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Effects of light absorption in the resist layer ati‐line exposure (wavelength 365 nm) are investigated using a newly developed clear resist. Exposure independent absorption (‘‘Bparameter’’ proposed by Dill) atiline of the new resist is ∼ (1)/(3) (0.083 μm−1) that of a conventionalg‐line‐use resist used for comparison. Both resists have nearly equal exposure dependent absorption (‘‘Aparameter’’) atiline and development characteristics. The only difference between the two resists from the viewpoint of resolution is theBparameter. Thus, it is clarified that a decrease in theBparameter by a factor of (1)/(3) made a 20% improvement in resolution capability and produced a nearly square shaped resist‐pattern profile.

ISSN:1071-1023    

DOI:10.1116/1.584713

出版商:American Vacuum Society    

年代:1989

数据来源: AIP

摘要:

Image contrast and edge slope are frequently used to assess image quality. But in the case of two‐dimensional geometries, the definition of contrast is not appropriate, as the maximum and minimum values of intensities may be different at the center, corners, etc. Similarly, edge slope may be different in different planes. Recently, a figure of merit (FOM) has been proposed to evaluate the image quality of two‐dimensional structures by a single parameter. In this paper, both contrast and FOM have been calculated as a function of the parameters of the optical system. It has been shown that in the case of near micron geometries, the variation in the contrast and edge slopes is sometimes misleading, whereas the FOM gives more accurate information of the image fidelity.

ISSN:1071-1023    

DOI:10.1116/1.584714

出版商:American Vacuum Society    

年代:1989

数据来源: AIP