W. M. Hooke

Observation of multiple nearly monoenergetic electron production by heated pyroelectric crystals in ambient gas

Multiple production of nearly monoenergetic electrons at a given pyroelectric crystal surface charge density is observed on cooling or heating the crystal in ambient gas. Typically, the +z base of a 5 mm diam×5 mm crystal of LiNbO3 is heated to 100 °C and then let cool to 23 °C in dry N2 at 10−2–10−6 Torr. The electron spectrum consists of a series of peaks equally spaced in energy and having decreasing intensity with order superimposed on a continuously decreasing background. The higher-order peaks and the high-energy continuum are due to two or more electrons hitting the surface barrier detector within its resolving time (∼1 μs).

TWO NEW PLANAR COIL DESIGNS FOR A HIGH PRESSURE RADIO FREQUENCY PLASMA SOURCE

Two planar coil designs for a high pressure rf plasma source are investigated using spectroscopic techniques and circuit analysis. In an Ar plasma a truncated version of the commonly used ‘‘spiral’’ coil is found to produce improvements in peak electron density of 20% over the full version. A coil with figure‐8 geometry is found to move plasma inhomogeneities off of center and produce electron densities comparable to the spiral coils. Both of these characteristics are advantageous in industrial applications. Coil design characteristics for favorable power coupling are also determined, including the necessity of closed hydrodynamic plasma loops and the drawback of closely situated antiparallel coil currents.

Diamond deposition using a planar radio frequency inductively coupled plasma

A planar radio frequency inductively coupled plasma has been used to deposit diamond onto scratched silicon. This plasma source has been developed recently for use in large area semiconductor processing and holds promise as a method for scale up of diamond growth reactors. Deposition occurs in an annulus which coincides with the area of most intense optical emission from the plasma. Well‐faceted diamond particles are produced when the substrate is immersed in the plasma.