Low resistivity copper germanide on (100) Si for contacts and interconnections

Abstract

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Microstructural and electrical properties of Cu-germanide formed on p-type Ge wafer

“…1 shows the GIXRD results taken from Cu films deposited on p-type Ge substrate after RTA process at the temperatures in the range of 300e700 C. The GIXRD plots clearly revealed that the solid-state reaction between Cu and Ge driven by RTA process led to the formation of Cu-germanide. In particular, regardless of RTA temperatures, the Cu 3 Ge having orthorhombic structure with lattice constants of a ¼ 0.528 nm, b ¼ 0.422 nm, and c ¼ 0.451 nm (space group 59) was the only phase observed in present samples, which was quite similar to the previous reports [22,23]. Additionally, no Bragg peaks corresponding to pure Cu were detected in all samples.…”

“…Namely, RTA process above 500 C led to the agglomeration of Cu 3 Ge. A similar behavior was also observed by Borek et al and Lai et al [20,23]. They reported that the Cu 3 Ge film starts to agglomerate at 550 C and completely lose its structural integrity after annealing at 600 C. In particular, Cu 3 Ge grains embedded in pit-like structures being rectangular in shape was observed in the sampled annealed at 700 C, of which detailed structural analysis will be shown in TEM and SEM results in the following.…”

Thermodynamic assessment of the Cu–Ge binary system

“…The germanides including Cu-Ge [1], Cr-Ge [2], Co-Ge [3], Ni-Ge [4] and Ti-Ge [5] have been considered recently in Ge-based CMOS to minimize the sheet resistance and to achieve low contact resistances on gate source and drain areas. Interface reactions between TM and Ge are critically important for the reliability of microelectronic devices.…”

“…Transition metal (TM) germanides have attracted much attention in the high-speed complementary metal oxide semiconductor (CMOS) technology because of their low room-temperature resistivity, high thermal stability and good adherence to silicon substrates [1][2][3][4][5]. The germanides including Cu-Ge [1], Cr-Ge [2], Co-Ge [3], Ni-Ge [4] and Ti-Ge [5] have been considered recently in Ge-based CMOS to minimize the sheet resistance and to achieve low contact resistances on gate source and drain areas.…”

Selective chemical vapor synthesis of Cu3Ge: Process optimization and film properties

“…6a and d) shows Cu 3 Ge layers exhibited sharp and planar interfaces with the underlying surfaces [3,7,17]. Such sharp interfaces of the films may be crucial for contact formation and shallow junction devices [9,14,15,35]. In addition, this low temperature process avoids the morphological instability and new interface phase formation which are otherwise noticed in the PVD-techniques after thermal annealing [6,22,34].…”