Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Process simulation of Ge nanocluster formation from GeO2 dots in SiO2

Heinig, K.-H.; Novikov, P. L.

The control of the MOSFET channel by nanoclusters within the gate oxide, which are charged/decharged due to direct e--tunneling, provides a conceptually very simple non-volatile memory. The development of reliable processes for the production of the required nanocrystals on an industrial scale is a big challenge to current research. The two processes being favored at present are the self-organization of nanocluster-delta-layers after ion implantation [1] and the deposition of Si aerosols [2]. Here, we present an alternative process taking advantage of the well-known self-assembling of Ge quantum dots on (001)Si [3,4] in combination with chemical reduction of GeO2 by Si during thermal treatment [5]. Using process simulations it will be studied, how, in comparison to pure thermal treatment, ion-irradiation induced detachment of Si monomeres from the Si/SiO2 interface accelerates the Ge precipitation due to the GeO2+Si --> SiO2+Ge reaction. For our study it was assumed that self-assembled Ge nanoclusters on Si [3,4] were covered by a Si layer, and, finally, oxidized under special conditions [5] which suppresses Ge segregation. The resulting thin gate oxide with embedded GeO2 clusters is the starting point of our kinetic Monte-Carlo simulations. In an fcc-cell of about 256000 lattice points having periodic boundary conditions in the interface plane, Ising-model-like interactions in the two-component system (Si and Ge) and the reaction GeO2+Si-->SiO2+Ge are taken into account. Additionally, according to ion beam mixing estimated by TRIM calculations, atomic displacements of Si bulk and nanocluster atoms have been considered.
[1] K.H.Heinig, B.Schmidt,.M.Strobel, H.Bernas, Mat.Res.Soc.Proc. v.650(2001).
[2] H. Atwater, J.W. De Blauwe et al., Mat.Res.Soc.Proc. v.638(2001).
[3] F. Jensen, J.W. Petersen, S.Y. Shiryaev, A.N. Larsen, Nanotechn. 7, 117 (1996).
[4] O.Pchelyakov, Y.Bolkhovityanov, A.Dvurechenskii, Thin Solid Films 367, 75 (2000).
[5] Y.-C.King, T.-J.King, C.Hu, Int.Electron Dev. Meeting Technical Digest (1998), 115.

Keywords: nanocluster; Ge; memory; ion irradiation; atomistic simulation

  • Lecture (others)
    EC project meeting NEON, Uni Aarhus, Denmark, August 19-21, 2001

Publ.-Id: 4953