06534395 is referenced by 450 patents and cites 5 patents.

Thin films are formed by atomic layer deposition, whereby the composition of the film can be varied from monolayer to monolayer during cycles including alternating pulses of self-limiting chemistries. In the illustrated embodiments, varying amounts of impurity sources are introduced during the cyclical process. A graded gate dielectric is thereby provided, even for extremely thin layers. The gate dielectric as thin as 2 nm can be varied from pure silicon oxide to oxynitride to silicon nitride. Similarly, the gate dielectric can be varied from aluminum oxide to mixtures of aluminum oxide and a higher dielectric material (e.g., ZrO

2

) to pure high k material and back to aluminum oxide. In another embodiment, metal nitride (e.g., WN) is first formed as a barrier for lining dual damascene trenches and vias. During the alternating deposition process, copper can be introduced, e.g., in separate pulses, and the copper source pulses can gradually increase in frequency, forming a graded transition region, until pure copper is formed at the upper surface. Advantageously, graded compositions in these and a variety of other contexts help to avoid such problems as etch rate control, electromigration and non-ohmic electrical contact that can occur at sharp material interfaces.

Title
Method of forming graded thin films using alternating pulses of vapor phase reactants
Application Number
9/800757
Publication Number
6534395 (B2)
Application Date
March 6, 2001
Publication Date
March 18, 2003
Inventor
Suvi P Haukka
Helsinki
US
Ivo Raaijmakers
Bilthoven
US
Christiaan J Werkhoven
Tempe
AZ, US
Agent
Knobbe Martens Olson & Bear
US
Assignee
ASM Microchemistry Oy
US
IPC
H01L 21/4763
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