We have characterized a new helicon plasma source with an end-launch antenna configuration. Power at 13.56 MHz is coupled via a four-turn flat spiral coil into an m=0 helicon mode with the application of a weak (B≳5 G) axial magnetic field. Plasma parameters were measured with Langmuir probes, and the structure and absorption of the helicon wave fields were determined with magnetic induction probes. Plasma densities of 1011–1012 cm−3 were produced in argon for pressures in the 1–100 mTorr range with a 5–60 G magnetic field. Radio frequency power absorption occurs primarily via collisionless Landau damping for pressures below 5–10 mTorr and collisional damping dominates at higher pressures. Single pass absorption occurs for magnetic fields less than 20 G. This source does not require a separate source chamber, and thus combines the compactness of flat coil inductively coupled sources with the advantages of remote plasma generation found in wave supported sources. The source can be easily optimized for a variety of operating conditions, because the helicon parallel wavelength is not constrained.

Thin films of niobium nitride are useful for their physical, chemical, and electrical properties. NbN superconducting properties have been utilized in a wide range of applications. Plasma-enhanced atomic layer deposition (PEALD) of NbN with (t-butylimido) tris(diethylamido) niobium(V) and remote H2/N2 plasmas has been investigated. Deposited film properties have been studied as a function of substrate temperature (100–300 °C), plasma power (150–300 W), and H2 flow rate (10–80 sccm). PEALD NbN films were characterized with spectroscopic ellipsometry (thickness, optical properties), four point probe (resistivity), x-ray photoelectron spectroscopy (composition), x-ray reflectivity (density and thickness), x-ray diffraction (crystallinity), and superconductivity measurements. Film composition varied with deposition conditions, but larger cubic NbN crystallites and increased film density at higher substrate temperatures and H2 flow rates lead to room temperature resistivity values as low as 173 μΩ cm and superconductivity critical temperatures as high as 13.7 K.

High-density magnetic-field-free plasma sources produce plasmas that are opaque to radio frequency (rf) fields in the 0–200 MHz frequency range. Thus plasma currents from a biased substrate flow to ground along reactor surfaces. We investigate some consequences of this rf skin effect in an inductively coupled plasma source with densities of 1011–1012 cm−3 in argon. Magnetic probe measurements confirm that capacitively coupled rf fields are localized near the reactor surfaces. Electric probes were used to measure the voltage on the surface of a biased platen without a substrate. We find that the rf wavelength and phase velocity along reactor surfaces are reduced by a factor of ∼5 compared to free space. This reduced wavelength is attributed to a surface wave which can be analyzed using a formalism similar to that for Trivelpiece–Gould modes.

Maintaining dimensional control and adequate throughput during the etching of submicron features requires plasma etch tools that operate at low pressures and high densities, such as inductively coupled plasmas (ICPs). Unfortunately, in this regime, it has proven difficult to achieve a stable, reproducible chemistry for selective oxide etching of contacts and vias. In particular, it is difficult to control the passivating polymer film which provides etching selectivity to silicon, nitride, and photoresist. As a first step toward sorting out the complicated oxide etching chemistry, we have measured and modeled the kinetics of the polymer film deposition in an ICP reactor for C2F6/H2 and CHF3 chemistries. Using a unique application of statistical design of experiments, we have explored the pressure range of 3–15 mTorr, power range of 300–2000 W, residence times from 0.5 to 1.0 s, and magnetic field from 0 to 24 G. Polymer deposition rates on a bare Si wafer are measured using a laser interferometer. The concentration of fluorocarbon radicals, CF, CF2, and CF3, are measured in the plasma using wavelength modulated infrared diode laser absorption spectroscopy. Additional measurements include actinometric F atom density and ion saturation current. These measurements are analyzed in terms of a polymer deposition model and the important physical phenomena are inferred. Significantly, we find a unique polymer deposition mechanism over the entire range of tool parameters including direct deposition of CF and ion-assisted deposition of CF2.

We fabricated a silicon micropore optic using deep reactive ion etching and coated by Pt with atomic layer deposition (ALD). We confirmed that a metal/metal oxide bilayer of AlO∼10  nm and Pt ∼20  nm was successfully deposited on the micropores whose width and depth are 20 μm and 300 μm, respectively. An increase of surface roughness of sidewalls of the micropores was observed with a transmission electron microscope and an atomic force microscope. X-ray reflectivity with an Al Kα line at 1.49 keV before and after the deposition was measured and compared to ray-tracing simulations. The surface roughness of the sidewalls was estimated to increase from 1.6±0.2  nm rms to 2.2±0.2  nm rms. This result is consistent with the microscope measurements. Post annealing of the Pt-coated optic at 1000°C for 2 h showed a sign of reduced surface roughness and better angular resolution. To reduce the surface roughness, possible methods such as the annealing after deposition and a plasma-enhanced ALD are discussed.