Preparation of AlN films by pulsed laser deposition using sintered aluminum nitride and elemental aluminum as raw materials

Abstract

Aluminum nitride films have been prepared on Si (100) substrates through two methods: basic pulsed laser deposition from sintered aluminum nitride ceramics and plasma-aided reactive pulsed laser deposition from elemental aluminum metal. The latter was performed in a nitrogen plasma environment generated from electron cyclotron resonance microwave discharge. The films deposited by both methods have been characterized by various techniques to examine the morphology and to determine the composition and structure. The formation of aluminum nitride compound was confirmed in the deposited films. The films prepared by basic pulsed laser deposition are found to contain oxygen impurities, while those obtained through the plasma aided method have exhibited a stoichiometric AlN composition. The films have shown better crystalline quality when prepared at higher temperatures, however, when aided by the nitrogen plasma the films contain pure AlN compound with much better crystalline quality even prepared at low temperatures. Mechanisms relevant to the deposition processes are also discussed with particular emphasis on the contributions of the nitrogen plasma to the film formation. A comparison of the different characteristic features associated with the films prepared by the two methods shows that the plasma aided method has reasonable advantages in preparing compound films.