Roughness and damage of a GaAs surface after chemically assisted ion beam etching with Cl2/Ar+

Dienelt, J.; Zimmer, Klaus; Sonntag, Justus von; Rauschenbach, B.; Bundesmann, Carsten

doi:10.1016/j.mee.2004.12.059

Cited by 5 publications

(5 citation statements)

References 26 publications

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“…A higher surface roughness value was obtained with increasing pressure, which could be caused by more chemically driven etching. 12 This result contrasts with the following mathematical expression on the evolution of surface roughness ͑͒ during etching of Si, which was reported by Petri et al 3 ϰ 1 It is understood that this expression is valid at low pressures below 3.75 mTorr, while our experiments were conducted above 10 mTorr. This discrepancy can be explained, by the recent work on the evolution of surface roughness during etching of Si.…”

Section: Discussioncontrasting

confidence: 72%

Section: Discussionmentioning

confidence: 67%

“…7 The decrease of surface roughness with higher ion energy during etching of TaN, TiN, and Si can be further supported by the work of Dienelt et al in which ion-beam etching results in the smoothest surface, followed by ion-assisted chemical etching and chemical dry etching; roughness caused by "ions" Ͻ roughness caused by "chemicals + ions" Ͻ roughness caused by chemicals. 12 This indicates that ion-beam etching using higher ion energy results in lower surface roughness. In that sense, a plasma condition using higher ion energy is advantageous in that a vertical profile can be attained while maintaining a low surface roughness.…”

Section: Resultsmentioning

confidence: 97%

“…This can be observed from other metal etchings; higher surface roughness is obtained with higher pressure, which can be caused by more chemically driven plasma etching. 12 Nonvolatile by-products.-The by-products generated during the etching of HfN and IrO 2 in Cl 2 are considered to be nonvolatile from the higher T b of their by-products, compared to TiN, TaN, and Si as shown in Table I. Etch rate and surface roughness of HfN and IrO 2 as a function of bias voltage are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Effects of Volatility of Etch By-products on Surface Roughness During Etching of Metal Gates in Cl[sub 2]

Hwang

Cho

Chan

et al. 2008

J. Electrochem. Soc.

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The evolution of surface roughening during etching of TaN, TiN, Si, HfN, and IrO 2 in Cl 2 was studied. It was observed that surface roughness depended on self-bias voltage and pressure; lower surface roughness was obtained at higher bias voltage and lower pressure during etching of TaN, TiN, and Si in Cl 2 whose boiling temperature of by-products is low, whereas the lower surface roughness was obtained at lower bias voltage and higher pressure during etching of HfN and IrO 2 in Cl 2 whose boiling temperature of by-products is high. It was understood that the contrasting trends from the experimental results originate from the different volatility of the etch by-products which were generated during etching in Cl 2 . It was also observed that, when bias voltage and pressure varied, surface roughness was inversely proportional to etch rate during etching of TaN, TiN, and Si, while surface roughness was proportional to etch rate of HfN and IrO 2 in Cl 2 . In addition, it was found that surface roughness increased as a function of etching time and the effect of etching time on surface roughness was more conspicuous during etching of HfN and IrO 2 .Plasma etching has been widely used to fabricate nanoelectronic devices such as integrated circuits, microelectromechanical system ͑MEMS͒ devices, and photonic devices. It plays a crucial role in current and future device performance. As new gate materials are introduced in complementary metal oxide semiconductor ͑CMOS͒ technology and device dimensions continue to shrink, surface properties induced by nonvolatile etch by-products become critical. In the CMOS technology, for example, new gate stacks consisting of metal electrodes/high dielectric constant ͑k͒ materials have been introduced to replace conventional poly-Si/SiO 2 . During plasma etching of the metal electrode/high-k gate stack, more nonvolatile byproducts were generated on the active area and a more roughened surface resulted, compared to the conventional poly-Si/SiO 2 gate stack. This surface roughening induced by nonvolatile by-products becomes more conspicuous, thereby affecting the device performance more sensitively, as device dimensions continue to be scaled down. 1,2 For instance during gate-stack etching of the metal electrode/high-k dielectric, the etched surface of metal-gate electrode is transferred to the underlying high-k dielectric. In turn, it leads to nonuniform over/etching of source/drain ͑S/D͒ regions; shallow S/Ds can be easily degraded.Evolution mechanisms on surface topography of silicon have been studied previously, motivated by concerns on device performance. 3-6 Petri et al. conducted a parametric study on surface roughening during single-crystal silicon etching by SF 6 plasma using atomic force microscopy ͑AFM͒. 3 They investigated the relations between the ratio of the ion flux over the reactive neutral flux ͑J i /J n ͒ and the surface roughness under various plasma conditions. Zhao et al. also performed a quantitative analysis on topography of the etched surface of Si͑100͒ to examine t...

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Section: Discussioncontrasting

confidence: 72%

Section: Discussionmentioning

confidence: 67%

Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Volatility of Etch By-products on Surface Roughness During Etching of Metal Gates in Cl[sub 2]

Hwang

Cho

Chan

et al. 2008

J. Electrochem. Soc.

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“…In discharges through pure chlorine, the etch rate is reported to vanish at low temperatures [76][77][78]. Detailed investigations of Rhallabi et al using chemically assisted ion beam etching revealed that the etch rate at low temperatures is dominated by the desorption rate of GaCl 3 (in fact: Ga 2 Cl 6 ) [79].…”

Section: Langmuir Probe Measurementsmentioning

confidence: 99%

Correlation of III/V semiconductor etch results with physical parameters of high-density reactive plasmas excited by electron cyclotron resonance

Franz

Meyer

Amann

2017

Plasma Sci. Technol.

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Reactive ion etching is the interaction of reactive plasmas with surfaces. To obtain a detailed understanding of this process, significant properties of reactive composite low-pressure plasmas driven by electron cyclotron resonance (ECR) were investigated and compared with the radial uniformity of the etch rate. The determination of the electronic properties of chlorine-and hydrogen-containing plasmas enabled the understanding of the pressure-dependent behavior of the plasma density and provided better insights into the electronic parameters of reactive etch gases. From the electrical evaluation of I(V ) characteristics obtained using a Langmuir probe, plasmas of different compositions were investigated. The standard method of Druyvesteyn to derive the electron energy distribution functions by the second derivative of the I(V ) characteristics was replaced by a mathematical model which has been evolved to be more robust against noise, mainly, because the first derivative of the I(V ) characteristics is used. Special attention was given to the power of the energy dependence in the exponent. In particular, for plasmas that are generated by ECR with EM modes, the existence of Maxwellian distribution functions is not to be taken as a self-evident fact, but the bi-Maxwellian distribution was proven for Ar-and Kr-stabilized plasmas. In addition to the electron temperature, the global uniform discharge model has been shown to be useful for calculating the neutral gas temperature. To what extent the invasive method of using a Langmuir probe could be replaced with the noninvasive optical method of emission spectroscopy, particularly actinometry, was investigated, and the resulting data exhibited the same relative behavior as the Langmuir data. The correlation with etchrate data reveals the large chemical part of the removal process-most striking when the data is compared with etching in pure argon. Although the relative amount of the radial variation of plasma density and etch rate is approximately 5%  , the etch rate shows a slightly concave shape in contrast to the plasma density.

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Chemical polishing method of GaAs specimens for transmission electron microscopy

Chang

2010

Micron

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Roughness and damage of a GaAs surface after chemically assisted ion beam etching with Cl2/Ar+

Cited by 5 publications

References 26 publications

Effects of Volatility of Etch By-products on Surface Roughness During Etching of Metal Gates in Cl[sub 2]

Effects of Volatility of Etch By-products on Surface Roughness During Etching of Metal Gates in Cl[sub 2]

Correlation of III/V semiconductor etch results with physical parameters of high-density reactive plasmas excited by electron cyclotron resonance

Chemical polishing method of GaAs specimens for transmission electron microscopy

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