Many materials systems are currently under consideration as potential replacements for SiO2 as the gate dielectric material for sub-0.1 μm complementary metal–oxide–semiconductor (CMOS) technology. A systematic consideration of the required properties of gate dielectrics indicates that the key guidelines for selecting an alternative gate dielectric are (a) permittivity, band gap, and band alignment to silicon, (b) thermodynamic stability, (c) film morphology, (d) interface quality, (e) compatibility with the current or expected materials to be used in processing for CMOS devices, (f) process compatibility, and (g) reliability. Many dielectrics appear favorable in some of these areas, but very few materials are promising with respect to all of these guidelines. A review of current work and literature in the area of alternate gate dielectrics is given. Based on reported results and fundamental considerations, the pseudobinary materials systems offer large flexibility and show the most promise toward success...

/pdf/high-k-gate-dielectrics-current-status-and-materials-zjvba0c4u8.pdf

High-κ gate dielectrics: Current status and materials properties considerations

http://files.janapv.webnode.cz/200000097-8a03f8afdf/ex_bias_nano.pdf

Exchange bias in nanostructures

Diamond may be grown at low pressures where it is the metastable form of carbon. Recent advances in a wide variety of plasma and electrical discharge methods have led to dramatic increases in growth rates. All of these methods have certain aspects in common, namely, the presence of atomic hydrogen and the production of energetic carbon-containing fragments under conditions that support high mobilities on the diamond surface. Some understanding of the processes taking place during nucleation and growth of diamond has been achieved, but detailed molecular mechanisms are not yet known. Related research has led to the discovery of a new class of materials, the "diamondlike" phases. Vapor-grown diamond and diamondlike materials may have eventual applications in abrasives, tool coatings, bearing surfaces, electronics, optics, tribological surfaces, and corrosion protection.

https://science.sciencemag.org/content/sci/241/4868/913.full.pdf

Low-Pressure, Metastable Growth of Diamond and "Diamondlike" Phases

Hafnium and zirconium silicate (HfSixOy and ZrSixOy, respectively) gate dielectric films with metal contents ranging from ∼3 to 30 at. % Hf, or 2 to 27 at. % Zr (±1 at. % for Hf and Zr, respectively, within a given film), have been investigated, and films with ∼2–8 at. % Hf or Zr exhibit excellent electrical properties and high thermal stability in direct contact with Si. Capacitance–voltage measurements show an equivalent oxide thickness tox of about 18 A (21 A) for a 50 A HfSixOy (50 A ZrSixOy) film deposited directly on a Si substrate. Current–voltage measurements show for the same films a leakage current of less than 2×10−6 A/cm2 at 1.0 V bias. Hysteresis in these films is measured to be less than 10 mV, the breakdown field is measured to be EBD∼10 MV/cm, and the midgap interface state density is estimated to be Dit∼1–5×1011 cm−2 eV−1. Au electrodes produce excellent electrical properties, while Al electrodes produce very good electrical results, but also react with the silicates, creating a lower e l...

Hafnium and zirconium silicates for advanced gate dielectrics

Pitting corrosion of aluminum

The pitting behavior of sputter-deposited Al binary alloy thin films was studied. Pitting and repassivation potentials were determined in 0.1M NaCl for samples in freshly deposited and air-aged states. Aging for several years in laboratory air increased the pitting potential for some of the alloy systems but had no effect on others The repassivation potentials, meaningful values for pits in thin films, were found to be very close to the pitting potentials of freshly-deposited films for many alloy systems. Stable pits initiate in these Al binary alloys a t potentials just above te value at which they would repassivate, indicating that pit growth considerations control the pitting process. By determining the pit anodic current density just before passivation it is shown that alloying improves pitting resistance through a reduction in the ability of pits to maintain the critical local environment necessary for growth. The influences of alloying on the passive film chemistry and on the tendency of the metal to repassivate (depassivation pH) are secondary in nature.

/pdf/on-the-pitting-resistance-of-sputter-deposited-aluminum-34rmdadupq.pdf

On the Pitting Resistance of Sputter‐Deposited Aluminum Alloys

A magnetic head slider having a protective coating on the rails thereof, the protective coating comprising a thin adhesion layer and a thin layer of amorphous hydrogenated carbon. The protective coating is deposited on the air bearing surface of the slider after the thin film magnetic heads are lapped to a chosen dimension, but before the pattern of rails is produced on the air bearing surface. The protective coating protects the magnetic head during the rail fabrication process and in usage in a magnetic recording system protects the magnetic head from wear and corrosion damage.

Magnetic head slider having a protective coating thereon

Etching processes are disclosed for producing a graded or stepped edge profile in a contact pad formed between a chip passivating layer (15) and a solder bump (10). The stepped edge profile reduces edge stress that tends to cause cracking in the underlying passivating layer (15). The pad comprises a bottom layer (14) of chromium, a top layer (12) of copper and an intermediate layer (13) of phased chromium-copper. An intermetallic layer (13) of CuSn forms if and when the solder is reflowed, in accordance with certain disclosed variations of the process. In all the variations, the solder (10) is used as an etching mask in combination with several different etching techniques including electroetching, wet etching, anisotropic dry etching and ion beam etching.

Etching processes for avoiding edge stress in semiconductor chip solder bumps

The permeability of the magnetic material in a thin‐film magnetic head is an important, but hard to characterize, parameter since the magnetic permeability depends on the head domain structure, the drive frequency, and the shape and size of the head. We have measured the high‐frequency permeability from 1 MHz to 300 MHz, hysteresis loops, and domain structure of unlaminated and multilayer magnetic thin‐films as a function of stripe width for arrays of long narrow stripes. Monolithic permalloyfilms and permalloyfilms laminated with SiO2 have been photolithographically patterned and ion‐milled to create 3 to 1000 μm wide rectangles, 1 cm long, with the hard axis oriented along the long axis of the rectangles. The high‐frequency permeability of each array of a given width is measured by the signal detected by a nonresonant butterfly‐coil pickup loop when the film is driven by a uniform radio‐frequency magnetic field generated by a strip‐line waveguide. The changes in domain pattern as the filmstructure and stripe width are varied are observed with a Kerr‐effect imaging microscope. In unlaminated films, which exhibit standard closure domains, a reduction in high‐frequency permeability is observed in agreement with simple models when the closure domains become a significant fraction of the film area. In laminated films with thick magnetic layers, the transition from the laminated domain state to closure domains as the stripe width is decreased occurs where expected from straightforward energy arguments. However, for magnetic layers less than 1 μm thick, where a transition from the easy‐axis laminated domain state to a uniform hard‐axis state is expected as the stripe width is reduced, the films first change from the easy‐axis state to a complicated, low‐Kerr‐contrast domain pattern before switching to the hard‐axis state at much larger widths than predicted. While the laminated state and hard‐axis permeabilities are frequency independent, the permeability of the intermediate state rolls off beginning at between 10 and 100 MHz. For still thinner magnetic layers (250 A), the multilayer retains the high‐permeability easy‐axis laminated domain state to the narrowest width measured, 3 μm.

High‐frequency permeability of laminated and unlaminated, narrow, thin‐film magnetic stripes (invited)

Thin films of ZrO2 and ZrO2–SiO2 were deposited by reactive dc magnetron sputtering. The optical properties, density, microstructure, and crystalline phase of pure ZrO2 films were found to be a function of deposition rate. In particular, the index of refraction could be varied from 1.77 to 2.13 by increasing the deposition rate from 11 to 720 A/min. The density of the films increased from 3.9 to 5.8 g/cm3 over the same deposition rate range. Small amounts of SiO2 (10 at. %) stabilized the mixed films in an amorphous phase. A linear relationship between index of refraction and SiO2 content was observed and, as in the case of pure ZrO2, increasing deposition rate resulted in mixed films with higher densities and indices for a fixed SiO2 content. The structure and optical properties of the mixed films remained unchanged with thermal cycling up to 500 °C.

Michael A. Russak

Papers

On the Pitting Resistance of Sputter‐Deposited Aluminum Alloys

Magnetic head slider having a protective coating thereon

Etching processes for avoiding edge stress in semiconductor chip solder bumps

High‐frequency permeability of laminated and unlaminated, narrow, thin‐film magnetic stripes (invited)

Reactive magnetron sputtered zirconium oxide and zirconium silicon oxide thin films