Charge storage and photoluminescence characteristics of silicon oxide embedded Ge nanocrystal trilayer structures

Abstract

Metal-oxide-semiconductor capacitors with a trilayer structure consisting of the cap gate oxide, sputtered SiGe layers and thermally grown tunnel oxide were fabricated on p-Si substrates. The trilayer structures were rapid thermal annealed at 1000 °C in nitrogen atmosphere for different durations. Cross-sectional transmission electron micrographs revealed the complete isolation of Ge nanocrystals in the sandwiched structure annealed for a longer duration. The optical and charge storage characteristics of trilayer structures were studied through photoluminescence spectroscopy and capacitance-voltage measurements, respectively. Under optimized annealing conditions, an enhancement of the charge storage capability of nanocrystals was observed in agreement with the optical emission characteristics.

Ellipsometric study of crystallization of amorphous Ge thin films embedded in SiO2

“…Ge nanocrystals embedded in SiO 2 have attracted a strong interest in the scientific community due to their potential applications in optoelectronics as light emitters, and in highspeed, low-power logic and memory devices [1,2]. A promising way to synthesize Ge nanocrystals within a SiO 2 matrix film is by high-temperature annealing of SiO 2 /a-Ge/SiO 2 trilayer structures [3].…”

Large capacitance-voltage hysteresis loops in SiO2 films containing Ge nanocrystals produced by ion implantation and annealing

“…Indeed, Ge-NC memory structures are strongly influenced by defect states at such interfaces in addition to effects due to the NCs. [8][9][10][11] It has been reported that ion implantation of Ge into thin SiO 2 layers on Si wafers, followed by annealing, results in Ge accumulation at the Si/ SiO 2 interface. [12][13][14] Diffusion of Ge atoms during annealing can alter the interface, thereby having a significant influence on the memory characteristics of such structures.…”

Metal nanocrystals as charge storage nodes for nonvolatile memory devices

“…Most studies have focused on the fabrication on Si and Ge nanocrystals in metal-oxidesemiconductor (MOS) structure [12][13][14][15][16][17][18][19][20]. In addition, atomicforce-microscopy (AFM) was utilized to inject charges in the nanocrystals [21][22][23].…”