Magnetron method

An external magnetic field has also been used to confine the plasma [143]. An arrangement where electromagnets are located under the cathode is known as the controlled plasma magnetron method [144]. The diffusion of electrons to the walls is prevented by the magnetic field between cathode and anode. This results in an increase in electron density, and consequently in a faster decomposition of silane and a higher deposition rate. At a deposition rate of 1 nm/s, device quality material is obtained [144]. In addition, a mesh is located near the anode, and the anode can by biased externally, both in order to confine the plasma and in order to control ion bombardment. 

In the late 1960s several major advances were made in the study of thermal electron reactions. These were based on the ECD, the extension of the magnetron method of studying electron molecule reactions to determine equilibrium constants for electron molecule reactions, and the invention of high-pressure thermal electron negative-ion sources for mass spectrometry [5-7], Electron swarms were also used to determine rate constants for thermal electron reactions [8, 9]. The electron affinities of molecules were measured using electron and alkali metal beams [10, 11]. Relative electron affinities were obtained from the direction of the reaction of a negative ion with a molecule [12, 13], Other major advances were photodetachment and photoelectron spectroscopy [14—17],... 

Other experimental procedures measure the energetics and kinetics of thermal electron reactions in the same manner as the ECD and NIMS. These are designated equilibrium methods. The direct capture magnetron method (MGN) and the individual determination of the individual rate constants k and k- for thermal electron reactions are also equilibrium methods. The latter was first carried out in an electron swarm (ES) for O2, but can be applied to any system to measure thermal electron reactions. These methods differ in how the electron and ion concentrations are generated and measured [6, 7],... 

Electron Affinities Determined Using the Magnetron Method... 

The electron affinity A = 0.771 0.005 was determined from a high-resolution (5 to 25 meV) photoelectron spectrum of NH2 [1]. A = 0.779 0.037 was obtained from a photoelectron spectrum at lower resolution [2]. Photodetachment-threshold measurements gave A = 0.744 0.022 [3] and 0.76 0.04 [4]. A = 0.76 0.14 was determined from pulsed ICR studies of ion-molecule reactions in ammonia [5]. A considerably higher value, A=1.2, resulted from applying the magnetron method [6]. 

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