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This letter reports the first replacement (Damascene) metal gate pMOSFETs fabricated with Ni/TaN, Co/TaN stacked electrode, where Ni or Co is in direct contact with the gate SiO/sub 2/, to adjust the electrode metal work function and TaN is used as the filling material for the gate electrode to avoid wet etching and CMP problems. The process is similar to the fabrication of traditional self-aligned polysilicon gate MOSFETs, except that in the back end (after the source/drain implants are activated) a few processing steps are added to replace the polysilicon with metal. Our data show that the Ni or Co/TaN gate electrode has the right work function for the pMOSFETs. The metal gate process can reduce the gate resistivity. Thermal stability of the stacked electrodes is studied and the result is reported in this paper. The damascene process flow bypasses high temperature steps (> 400/spl deg/C)critical for metal gate and hi k materials. This paper demonstrates that a low temperature anneal (300/spl deg/C) can improve the device performance. In this paper, the gate dielectrics is SiO/sub 2/.

Auger electron spectroscopy analyses of submicron features on semiconductor surfaces are routinely accompanied by analytical artifacts such as sample degradation and background contributions arising from electron beam scattering. Submicron analyses are commonly carried out at electron beam densities in excess of 1 A cm -2 and are especially damaging to silicon oxides. The evolution of oxide reduction is observed both as a loss of oxygen versus beam exposure and in a complementary growth of Si LVV and Si KLL elemental peaks. The O KLL signal intensity from a 1 μm 2 area of thermally grown oxide is found to decrease by 22% after exposure to a rastered 20 kV/10 nA beam for 10 min. Another aspect of submicron analysis is the contribution to survey spectra that originates when surrounding material is excited by backscattered electrons. Background contributions may dominate AES spectra even when the sample is flat and the probing beam is smaller than the feature of interest. Tungsten damascene contacts provide a useful platform for investigating this phenomenon in the absence of topography. Spectra have been collected from tungsten contacts of various sizes and the target and background contributions quantified. When a 0.25 μm diameter tungsten contact is probed with a narrow 20 kV beam, the W MNN signal intensity is determined to be only 70% of that emitted from a large tungsten structure. Target signal reduction coincides with increased signal contributions from the surrounding oxide.

The design and testing of an imaging band‐pass analyzer (BPA) consisting of two 90° spherical sectors operating in a magnetic‐field‐free region is described. Image electrons injected nearly parallel to one another and perpendicular to the first 90° sector are focused into an energy plane where electrons of desired energy are band‐pass filtered. A second 90° sector is used to recover the energy‐filtered image. With a 1‐mm aperture, energy resolution of 1% and spatial resolution of 0.01% of the main path radius are calculated and agree well with the test results over an image size of 12×12 mm2. The addition of this analyzer to our magnetic projection photoelectron microscope poses an additional technological problem in that the electrons are required to pass from a relatively high‐field area to a field‐free region without disruption of the image. Design considerations for a structure that abruptly terminates a magnetic field yet is transparent to image electrons are described.

The magnetic projection photoelectron microscope performs imaging photoelectron and photoabsorption spectroscopy with a lateral resolution of the order of microns. We review practical experience accumulated in two months of synchrotron-based operations. Theoretical limitations and practical issues related to count rates, elemental and chemical contrast and extraneous noise are discussed. A comparison is made between our experience with retarding field analysis and a conceptual imaging band-pass analyzer. Recent observations from surface diffusion experiments are presented.

A photoelectron microscope operating with a retarding field analyzer can exploit core level energy shifts in order to image Fermi‐level variations of semiconductor surfaces. Fermi‐level maps of cleaved n‐ and p‐type GaAs (110) resolved to better than 10 μm indicate lateral variations in the surface Fermi level which are often quite abrupt. In agreement with earlier, lower resolution work [J. M. Palau, E. Testemale, and L. Lassabatere, J. Vac. Sci. Technol. 19, 192 (1981)],1 Fermi‐level topography is found to be highly correlated with surface roughness as characterized by scanning electron microscope (SEM), optical microscope, and stylus profilometer. Defective fracture surfaces have two distinct characters within SEM resolution: linear defects (steps and ledges) that may extend over millimeters and smooth glassy areas. Both types of surface defects shift the Fermi level towards midgap. The largest defect derived pinnings encountered to date result in the Fermi level lying 0.5 eV above the valence‐band max...

We describe simple methods of soft X-ray dosimetry (1000–3000 eV) for synchrotron based X-ray lithography. These methods are generally applicable to other synchrotron installations and possibly to so-called “stand alone” X-ray sources. A double crystal monochromator of synthetic multilayer crystals was used to obtain narrow band X-rays for energy-dependent measurements. The quantum efficiency of a stainless steel vacuum photocathode is shown to be well modeled by a simple power law, and its use in measuring the quantum efficiency of semiconductor diodes is described. The photocathode modeling is used in conjunction with the monochromator to demonstrate that resist sensitivity depends uniquely on absorbed dose density. The validity of the modeling is discussed, and the limitations of each type of detector are outlined. Suggestions are made for the application of these inexpensive detectors to real time source calibration in practical X-ray lithography equipment.

With a keyboard and supporting system developed at Cornell University, input methods used to identify ideographs are adaptations of well-known schemes; innovation is in the addition of automatic machine selection of ambiguously identified characters.The unique feature of the Cornell design is that a certain amount of intelligence has been built into the machine. This allows an operator to take advantage of the fact that about 60% of Chinese characters in text are paired with other characters to form two-syllable compounds or phrase words. In speech and writing these pairings eliminate about 95% of the ambiguities created by ambiguously identified syllables.

The optical and mechanical properties of boron nitride vapor deposited at 400 °C are shown to degrade when exposed to synchrotron radiation. The extent of the damage and the rate at which the damage occurs are similar to that first reported by Johnson et al. Transmission through membranes of boron nitride was measured in situ during exposure to x rays. Membranes darkened considerably with the transmission through a typical membrane falling from 50% to 20% after absorbing ∼250 kJ/cm3 of x rays. Changes in local film stress were measured with a simple cantilever technique. Films originally in tension (∼5E8 dyne/cm2) were found to become compressive after absorbing 300 kJ/cm3 of x rays. Both forms of damage responded well to annealing. Fourier transform infrared (FTIR) and near‐edge x‐ray absorption measurements were made to discern the structural differences between degraded and unexposed films. No significant structural changes were observed. Boron nitride films deposited at higher temperatures (600 °C) pr...