In this work, the low-temperature process steps required for the realization of nano-crystal non-volatile memory cells are discussed. An amorphous silicon film, crystallized using a diode pumped solid state green laser irradiating at 532 nm, is proposed as an active layer. The deposition of the subsequent functional layers (e.g., gate oxide) can be done using CVD and ALD reactors in a cluster tool. We show that a high nanocrystal density (Si-NC), required for a good functionality of the memory device, can be obtained by using disilane (Si2H6) or trisilane (Si3H8, known as Silcore®) as precursors for LPCVD instead of silane, at a deposition temperature of 325 °C. The nanocrystals are encapsulated with an ALD-Al2O3 layer (deposited at 300 °C), which serves as oxidation barrier. The passivation of the realized structure is done with an ALD-TiN layer deposited at 425 °C. In this work, we realized Al/TiN/Al2O3/Si-NC/SiO2/Si(100) multilayer floating-gate structures, where the crystallized amorphous silicon film was for the time being replaced by a mono-crystalline silicon wafer, and the gate oxide was thermally grown instead of a low-temperature PECVD oxide. The structures were characterized in terms of their performance as memory cells. In addition, the feasibility to use laser crystallization for improving the amorphous silicon films (prior to the gate oxide deposition) was explored.
|Title of host publication||10th Annual Workshop on Semiconductor Advances for Future Electronics and Sensors (SAFE)|
|Place of Publication||Utrecht, The Netherlands|
|Number of pages||5|
|Publication status||Published - 29 Nov 2007|
|Event||10th Annual Workshop on Semiconductor Advances for Future Electronics and Sensors, SAFE 2007 - Veldhoven, Netherlands|
Duration: 29 Nov 2007 → 30 Nov 2007
|Publisher||Technology Foundation STW|
|Workshop||10th Annual Workshop on Semiconductor Advances for Future Electronics and Sensors, SAFE 2007|
|Period||29/11/07 → 30/11/07|
- SC-ICF: Integrated Circuit Fabrication
Brunets, I., Boogaard, A., Aarnink, A. A. I., Kovalgin, A. Y., Wolters, R. A. M., Holleman, J., & Schmitz, J. (2007). Low-temperature process steps for realization of non-volatile memory devices. In 10th Annual Workshop on Semiconductor Advances for Future Electronics and Sensors (SAFE) (pp. 504-508). Utrecht, The Netherlands: STW.