High-k gate stack on germanium substrate with fluorine incorporation

Abstract

In this letter, a postgate CF4-plasma treatment is proposed and demonstrated on germanium (Ge) metal-oxide-semiconductor capacitors and the effects of fluorine (F) incorporation have been studied on both high-k∕Ge gate stacks without any surface passivation and with Si surface passivation. Our results show that F is effectively introduced into the gate stack by CF4 treatment and segregates near high-k∕Ge interface. Electrical characteristics such as frequency dispersion, interface state density (Dit), and gate leakage are improved after F incorporation. Interface quality of high-k∕Ge gate stack is further improved by combining Si surface passivation and postgate CF4 treatment, with its Dit as low as 4.85×1011cm−2eV−1.

Ge incorporated epitaxy of (110) rutile TiO2 on (100) Ge single crystal at low temperature by pulsed laser deposition

“…These properties cause high defect densities at the interface between high-k and Ge and a large hysteresis in the capacitance-voltage (C-V) characteristic [8,9]. To overcome these problems, some groups have demonstrated the formation of stable GeO 2 [10,11] and the surface passivation of Ge such as GeN (GeON) passivation [12,13], Si passivation [14], and F passivation [15]. These approaches achieved the improvements of electrical properties such as reduced C-V characteristic hysteresis and reduced leakage current.…”

Effects of fluorine incorporation on the properties of Ge p-MOS capacitors with HfTiON dielectric

“…NH 3 treatment [8], atomic N surface nitridation [9], SiH 4 treatment [10], wet-NO pretreatment [11], AlN x passivation [12][13][14] and TaO x N y interlayer [7]. Also, it was reported that fluorine was a good passivant for HfO 2 / SiO 2 interface due to formation of strong Hf-F and Si-F bonds [15,16], while Xie et al [17] used F to anneal the HfO 2 in Ge MOS transistors for improved electrical properties.…”

Improved electrical characteristics of TaN/Al2O3/In0.53Ga0.47As metal-oxide-semiconductor field-effect transistors by fluorine incorporation

“…[9][10][11] Recently, fluorine ͑F͒ incorporation into the high gate dielectric has been shown to improve device performance and reliability on Si substrate [12][13][14] and Ge substrate. 15 Seo et al 13 incorporated F into high gate dielectric by F 2 annealing in the presence of UV radiation, passivating high bulk and high / Si interface defects. Mitani et al 14 introduced F into gate dielectrics by F implantation and followed by annealing.…”

“…12 The similar mechanism has been reported on Ge substrate that Ge-F and Hf-F bonds formation at high / Ge interface and in HfO 2 gate dielectric results in reduction in interface and bulk traps, respectively. 15 In this letter, we explore the possibility of its inclusion as the gate dielectric in InGaAs-based devices. We demonstrate the impact of postgate CF 4 plasma treatment on In 0.53 Ga 0.47 As n-MOSFET.…”