Effects of initial layer surface roughness on GMR performance of Si/Cu/NiFe/Cu/Co/Cu/NiFe dual spin-valves for MRAM

Author

Seongtae Bea ; Matsushita, Nobuhiro ; Zurn, Shayne ; Sheppard, Larry ; Torok, E. James ; Judy, Jack H.

Author_Institution

Dept. of Electr. & Comput. Eng., Minnesota Univ., Minneapolis, MN, USA

Volume

36

Issue

5

fYear

2000

fDate

9/1/2000 12:00:00 AM

Firstpage

2850

Lastpage

2852

Abstract

The effects of initial layer surface roughness on GMR performance for magnetoresistance random access memory (MRAM) have been investigated as a function of Cu buffer layer thickness and input sputtering power of Si/Cu/NiFe/Cu/Co/Cu/NiFe dual spin valves. The GMR ratio increased up to 4.5% as Cu buffer layer thickness decreased from 30 nm to 5 nm and input sputtering power increased from 50 to 300 W. According to ex-situ atomic force microscopy and Auger electron spectroscopy analyzes, the higher GMR ratio is mainly due to smoother interfacial roughness of the multilayers and smaller oxygen content inside the GMR stacks. It is revealed that the initial layer surface roughness is dependent upon the deposition parameters and film thickness plays a key role in determining the surface roughness and magnetic coupling of subsequent magnetic multilayers

Keywords

Auger electron spectra; Permalloy; atomic force microscopy; cobalt; copper; giant magnetoresistance; interface roughness; magnetic heads; magnetic multilayers; random-access storage; silicon; spin valves; sputtered coatings; surface topography; 5 to 30 nm; Auger electron spectroscopy; GMR performance; GMR ratio; Si-Cu-NiFe-Cu-Co-Cu-NiFe; buffer layer thickness; deposition parameters; dual spin-valves; ex-situ AFM; initial layer surface roughness effect; input sputtering power; interfacial roughness; magnetic RAM; magnetic coupling; magnetic multilayers; Atomic force microscopy; Atomic layer deposition; Buffer layers; Giant magnetoresistance; Magnetic multilayers; Random access memory; Rough surfaces; Spin valves; Sputtering; Surface roughness;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.908606

Filename

908606