Gas Product Profile – Disilane Si2H6

The current proliferation of electronic devices, including smart phones, music players, tablets, and cameras has created a huge demand for semiconductor memory chips. New and more complex applications and functionality for many of these devices is adding to that demand.

Additionally, increased memory capacity per device is driving required improvements in both flash and DRAM (Dynamic Random Access Memory) chip manufacturing.

Semiconductor memory manufacturers have responded by shrinking device critical dimensions, thereby adding capacity and reducing power requirements. This has resulted in many challenges in the manufacturing process requiring many new materials with unique characteristics. Traditionally, silane has been used for most process steps requiring the deposition of polycrystalline silicon. (See “Gas Product Profile: Silane,” CryoGas, February 2012, p. 34.) However, disilane has been found to have significant advantages over silane, including an overall higher deposition rate at a significantly lower processing temperature. An additional benefit is that the use of disilane results in a smoother, highly uniform film while minimizing voids. This has become increasingly important in the deposition process as chip dimensions continue to shrink and the number of device layers increase. The combination of these benefits provides significant device performance improvements and increased throughput in the manufacturing process.

_{However, disilane has been found to have significant advantages over silane, including an overall higher deposition rate at a significantly lower processing temperature.}

Disilane has been adopted for several critical memory chip manufacturing steps including self-aligned contacts for DRAM, plate polysilicon for the capacitor electrode for DRAM, and for the first layer of gate polysilicon deposition for flash memory devices. Disilane is also being adopted for key process steps in logic devices to take advantage of its deposition properties.