Formation of Ge nanocrystals in HfAlO high-k dielectric and application in memory device

Abstract

Formation of Ge nanocrystals embedded in HfAlO high-k dielectric by co-sputtering of HfO2, Al2O3, and Ge, followed by rapid thermal annealing was demonstrated. Analysis by transmission electron microscopy and x-ray photoelectron spectroscopy confirmed the formation of nonoxidized Ge nanocrystals with a minimum size of about 5nm embedded in HfAlO dielectric. We also demonstrated the application of such nanocrystals in nonvolatile memory devices, achieving a 2.2V memory window as obtained from the C–V characterization of the memory device.

Electronic structure and interfacial properties of Ge nanoclusters embedded in amorphous silica

“…Embedded nanoparticles also show interesting physical phenomenon as compared to the isolated nanoparticles or bulk materials [7] and find new applications in electronics devices [8][9][10]. Germanium nanoparticles in silica glass matrix was found to show super heating during melting and super cooling during crystallization which lead to hysteresis of the melting temperature as high as 17% [7].…”

Structural properties of Ge nanocrystals embedded in sapphire

“…However, a few studies have reported on Ge nanocrystals embedded in other matrix materials such as Al 2 O 3 , 1 SiC, 2 AlN, 3 and HfAlO. 4 Because the surfaces and interfaces of nanoscale materials can play a dominant role in determining their properties, it is interesting to compare the properties of nanocrystals embedded in different matrices. For example, though quantum mechanical models predict efficient size-dependent photoluminescence from group IV semiconductor nanocrystals, the reported luminescence from silica-embedded Ge nanocrystals has mostly been attributed to defects within the oxide or at the oxide/nanocrystal interface.…”

Effect of Al addition on the microstructure and electronic structure of HfO2 film

“…6,7 It is also expected that Al addition will enlarge the band gap of HfO 2 . 8 Although numerous papers have appeared in the past two years addressing the physical/electrical properties of hafnium aluminate as a gate dielectric, [9][10][11][12] the basic microstructure and electronic structure of these amorphous materials remain unclear.…”