Precursors support DRAM and PRAM advancements

Air Products has introduced its Extrema STO and GST precursors in support of continuous advancements in Dynamic Random Access Memory (DRAM) and Phase-Change Random Access Memory devices (PRAM).

The company's Extrema STO precursors are said to improve manufacturers' ability to better deposit ultra-high k dielectric films using atomic later deposition (ALD) for use in 22nm to 15nm DRAM devices.

Dr Laura Matz, technical manager for advanced memory materials at Air Products, said: 'STO is a crystalline compound - Strontium Titanium Oxide - which has a high dielectric constant.

'This facilitates the further miniaturisation of the memory element, increasing the amount of data stored on each chip.

'Air Products' Extrema Sr and Extrema Ti STO precursors have been employed to deposit STO films which exhibit high dielectric constant and low electrical leakage,' she added.

Extrema GST precursors allow thermal ALD of conformal films critical to the manufacture of PRAM devices at 22nm and below.

Matz said: 'GST is an alloy of Germanium, Antimony (chemical symbol Sb) and Tellurium, which can be made to change phase under the influence of temperature.

'It has been the basis of optical storage devices such as DVD-RW for some time and is now being readied for use in solid state memory.

'Extrema Ge, Extrema Sb and Extrema Te GST precursors have been employed to deposit conformal GST films with good compositional uniformity.

'This attribute is critical for fabricating the confined contacts present in PRAM devices,' she added.

A key feature of these precursors is that they work together to enable compositional control of challenging new films.

Until now, semiconductor devices have generally employed simple, binary films (such as Hafnium Oxide) which comprise only two elements (Hafnium and Oxygen).

More recent structures have employed laminates of two binary films (for example, Zirconium Oxide and Aluminium Oxide) to improve performance.

However, the harmonious use of three elements to form a single, precisely controlled ternary film has presented a significant challenge to semiconductor manufacturers.

Air Products will be presenting these materials at the upcoming ALD2010 Conference in Seoul, Korea from 20 to 23 June.

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