EFFECT OF SILICON PROCESSING ON GIANT MAGNETORESISTANCE

The primary objective of this study is to determine the effect of sili con wafer processing parameters on giant magnetoresistance (GMR). Ther mally oxidized silicon wafers serve as substrates for alternating laye rs of NiFeCo and Cu (2.0-2.5 nm). SiO2 films prepared in the laborator y are loaded into the sputtering chamber along with commercially oxidi zed wafers for comparison purposes. Four process parameters are system atically varied-oxidation method, postoxidation anneal (POA), oxide th ickness, and oxidation temperature. Preliminary results indicate the t wo most influential processing parameters are the method of oxidation (dry oxygen or wet steam) and a POA. In contrast, GMR values do not se em to vary greatly for various oxidation or POA temperatures in the ra nge 800-1000 degrees C. We present GMR results of NiFeCo/Cu multilayer s on oxidized silicon substrates formed by various processing methods. GMR is observed for all films, with the magnitude of the effect incre asing for substrates oxidized by ''wet'' methods and oxidized substrat es that include a POA (1000 degrees C, nitrogen atmosphere, 20 min) pr evious to sputter deposition of the multilayers. Our data suggest that the GMR of the multilayer stack is sensitive to changes at the Si-SiO 2 interface. (C) 1996 American Vacuum Society.