Tyler Lowrey

MOCVD

Phase-change memory devices fabricated using MOCVD-deposited 30% Ge, 20% Sb, and 50% Te atomic composition, GST325 alloy, are fully characterized. In 100-nm-size test devices, a more than 2x reduction of reset current and set resistance were demonstrated compared with equivalent devices using PVD-deposited GST225. The devices show set speeds of 175-260 ns and a ten-year data-retention temperature of 102°C, comparable with devices made using a PVD GST225 alloy. Cycle endurance of up to 7 × 109 was also demonstrated.

\hbox{Ge}_{3}\hbox{Sb}_{2}\hbox{Te}_{5}

We have demonstrated conformal deposition of amorphous GeSbTe films in high aspect ratio structures by MOCVD. SEM analysis showed the as-deposited GeSbTe films had smooth morphologies and were well controlled for void free amorphous conformal deposition. GeSbTe films adhere well to SiO 2 , TiN, and TiAlN. The morphology and adhesion are stable in 420°C post process. By annealing at 365°C, amorphous GeSbTe films converted into crystalline GeSbTe with polycrystalline grain sizes of 5nm. Film resistivity in the crystalline phase ranged from 0.001 to 0.1 Ω-cm, suitable for device applications. Phase change devices fabricated with confined via structures filled with MOCVD GeSbTe showed cycle endurances up to 1×10 10 with a dynamic set/rest resistance of two orders of magnitude.