CHARACTERIZATION OF THE LINEAR ARC-DISCHARGE (LAD) SOURCE FOR FILM DEPOSITION

The linear arc discharge (LAD) source is a parallel plate hollow catho de with a magnetic field perpendicular to the plates near the outlet s lit of the cathode. The hollers cathode discharge is generated by radi o frequency (rf) power and is confined mainly to the outlet region of the cathode slit. The magnetic confinement increases the power density thereby forming hot linear tunes along the cathode plates at the cath ode outlet. These zones represent the main supply of the cathode mater ial, and in a cathode arc regime they contribute substantially to the thermionic emission of electrons. The plasma density measured by a dou ble Langmuir probe 15 cm below the cathode outlet reaches the order of 10(12) cm(-3) already at rf power greater than or equal to 300 W. The growth rate of Ti films decreases as a second order polynomial functi on of the cathode outlet to substrate distance. The growth rate of TiN films depends on the content of nitrogen in Ar. At a N-2 content in A r of less than 0.5%, the reactive film growth rate can reach or even e xceed the growth rates of purr Ti metal films. Characteristics of the hollow cathode discharge exhibit a gradual dependence on the distance between the cathode plates in the range 6-2 mm. A dramatic change of t he hollow cathode characteristics was found at the distance of 300 +/- 50 mu m between the plates. (C) 1997 Elsevier Science S.A.