Nanoporous metallic thin films prepared by dry processes

Tran, Hieu Trung,Byun, Ji Young,Kim, Sang Hoon Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.764 No.-

<P><B>Abstract</B></P> <P>Nanoporous Pt and Au thin films were prepared by dry etching methods and compared to those prepared by conventional wet etching (dealloying). While reactive ion etching (RIE) and deep RIE methods did not yield nanoporous structures with high roughness factors (<5), gentle XeF<SUB>2</SUB> dry etching yielded thin metallic nanoporous films (∼200 nm) with high enough roughness factors (∼40). The nanoporous films were as good as those prepared by wet etching using 3% HF solution in terms of thickness and roughness factors. Sensing performance of nanoporous Pt films prepared by XeF<SUB>2</SUB> dry etching was as good as that of wet-chemically dealloyed nanoporous Pt films for glucose sensing.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanoporous Pt and Au thin films 100–200 nm thick were fabricated by all dry processes from Pt-Si and Au-Si alloy films. </LI> <LI> Alloy films were prepared by cosputtering metal and Si targets at the same time. </LI> <LI> Si etching was carried out by XeF<SUB>2</SUB>, RIE and deep RIE dry etchings. </LI> <LI> Dry etched nanoporous thin films showed sensing performance as good as that of wet etched nanoporous films. </LI> </UL> </P>

실리콘 반도체 에칭기술개발 동향에 관한 조사연구

신영두,이진구 동국대학교 산업기술환경대학원 1994 산업기술논총 Vol.2 No.-

This paper describes investigation and analysis of Si wafer find-line processes from 1960's up to present based on U.S. Patent No. 4,941,941 entitled " METHOD OF ANISOTROPICALLY ETCHING SILICON WAFERS AND WAFER ETCHING SOLUTION". This study is intended to classify techniques on wet etchants from chemicals mainly used in the reference above and 9 patents, and also includes reviews on both physical and chemical features of wet etching and, further more, comparative explanation of wet and dry etching. The characteristics of low temperature and low speed, of the wet etching processes and some limitations of the informations, given in U.S. Patent No. 4,941,941 and 9 patents, are mainly investigated and analysed, and, then, the dry etching processes are simply discussed as a substitution for the fin-line Si processes. And, finally, future possible development of other kinds of chemical etchants is suggested.

Ultra-low rate dry etching conditions for fabricating normally-off field effect transistors on AlGaN/GaN heterostructures

Kim, Zin-Sig,Lee, Hyung-Seok,Na, Jeho,Bae, Sung-Bum,Nam, Eunsoo,Lim, Jong-Won Elsevier 2018 Solid-state electronics Vol.140 No.-

<P><B>Abstract</B></P> <P>Enhancement-mode transistors with uniform turn-on threshold voltage (V<SUB>th</SUB>) can be achieved using low damage and low rate gate recess etching techniques. In this work, dry etching conditions for a AlGaN/GaN heterostructure with an ultra-low etching rate of 1.5 nm/min were demonstrated and we succeeded the possibility to achieve a low etch rate of an AlGaN/GaN heterostructure in a Cl<SUB>2</SUB>/BCl<SUB>3</SUB> plasma using inductively coupled plasma (ICP). The etching development was successfully implemented in the achievement of a normally-off GaN/AlGaN based transistor. The optimal recess depth was determined after fabrication of various devices with different recess depth values and with various dry etching conditions and after examining the performances of fabricated devices various conditions, and determining the dependence of recess time. The optimized etching condition resulted in low damage and smooth morphology of the etched AlGaN/GaN surfaces. Fine control of the depth of the gate region recess was achieved for the AlGaN/GaN heterostructure without any etch-stop layer, and validated for the fabrication of field effect transistors (FETs) using conventional processes. The fabricated normally-off Al<SUB>2</SUB>O<SUB>3</SUB>/AlGaN/GaN MOSFETs delivered a high positive V<SUB>th</SUB> of +5.64 V with a low off-state leakage current of ∼10<SUP>−7</SUP> A/mm and lower current collapse.</P>

Surface morphological evolution of crystalline Si during chemical dry etching using F radicals and NO gas

Ahn, J.H.,Heo, W.,Jung, C.R.,Lee, N.-E. Elsevier 2011 Current Applied Physics Vol.11 No.5

<P><B>Abstract</B></P><P>In this study, changes in the surface morphology of single crystalline Si during chemical dry etching using F radicals and direct-injected nitric oxide (NO) gas were investigated. When NO gas was injected into a chamber supplied with F radicals from NF<SUB>3</SUB> input gas generated from a remote plasma source, the single crystalline Si surface was textured and roughened during the chemical dry etching. It was found that the roughened morphology varied as a function of the NO gas flow rate, the total gas flow rate of NF<SUB>3</SUB> and NO gases, and the etching time. The roughened morphology that developed during the fast chemical dry etching of silicon led to a reduction in the reflectance of visible light.</P> <P><B>Highlights</B></P><P>► Single crystalline Si surface was effectively textured and roughened during the chemical dry etching using F radicals and direct-injected nitric oxide (NO) gas. ► The roughened morphology of the textured surface varied as a function of the NO gas flow rate, the total gas flow rate of NF3 and NO gases, and the etching time. ► The roughened morphology of silicon led to the reduced reflectance as low as 6.07% at a wavelength of 750 nm.</P>

HDP를 이용한 실리콘 단결정 Deep Dry Etching에 관한 특성

박우정,김장현,김용탁,백형기,서수정,윤대호 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.6

현재 전기 . 전자 기술의 추세는 소형화를 비롯하여 집적화, 저전력화, 저가격화의 장점을 가진 MEMS(Micro Electro Mechanical Systems) device의 개발에 주력하고 있으며, 이를 위해서는 고종횡비와 높은 식각 속도를 가진 HDP(High Density Plasma) etching 기술 개발이 필수적이라 할 수 있다. 이를 위하여 우리는 Inductively Coupled Plasma(ICP) 장비를 이용하여 각 공정 변수에 의한 실리콘 deep trench식각 반응을 연구하였다. 실험 공정 변수인 platen power, etch/passivation cycle time에서 etching 단계 시간에 따른 변화와 SF$_{6}$:C$_4$F$_{8}$ 가스유량을 변화시켜 연구하였으며 또한 이들의 profile, scallops, 식각 속도, 균일도, 선택비도 관찰하였다. The present tendency of electrical and electronics is concentrated on MEMS devices for advantage of miniaturization, intergration, low electric power and low cost. Therefore it is essential that high aspect ratio and high etch rate by HDP technology development, so that silicon deep trench etching reactions was studied by ICP equipment. Deep trench etching of silicon was investigated as function of platen power, etch step time of etch/passivation cycle time and SF$\_$6/:C$_4$F$\_$8/ flow rate. Their effects on etch profile, scallops, etch rate, uniformity and selectivity were also studied.

Ion Beam을 이용한 Ni-Co-Cu Alloy Thin Film의 Dry Etching에 관한 연구

안정식,장문식,이규용 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

Much effort has been made worldwide in dry etching of new thin film by IBE, IRE, ECR etc. In this study, dry etching of Ni-Co-Cu alloy thin film grown by IBD on a glass substrate was performed using Ar^(+) or N_(2)^(+) ions of 2KeV as a function of ion dose by high current DuoPigatron type ion source. The experimental results showed that surface morphology of the Ar^(+) beam etched PR was rough at 2KeV energy, but the N_(2)^(+) beam etched was smoother. It could be surmised that an increase in the atomic radius was correlated to an increase in the energy of the bombarding ions, which leaded to damaged PR layer due to the thermal phenomena, such as thermal spike, cascade, etc. in PR surface. As the result, pattern were destroyed partially with the melted and flowed over area. Dry etching of the thin film, in turn, was more successful in N_(2)^(+) beam etching than in Ar^(+) beam and it seemed that N_(2) ion was more effective in removing the currently used PR. Observed results from SEM showed that the resolution was increased with increasing N_(2) ion dose up to 3.6X10^(19) ions/cm^(2) at 2KeV, beyond this proper ion dose the resolution was decreased and leaded the damaged pattern.

새로운 ICP 장치를 이용한 고온 초전도체의 Dry Etching과 기존의 Wet Etching 기술과의 비교

강형곤,임성훈,임연호,한윤봉,황종선,한병성 한국전기전자재료학회 2001 전기전자재료학회논문지 Vol.14 No.2

In this report, a new process for patterning of YBaCuO thin films, ICP(inductively coupled plasma) method, is described by comparing with existing wet etching method. Two 100㎛ wide and 2mm long YBaCuO striplines on LaAlO$_3$ substrates have been fabricated using two patterning techniques. And the properties were compared with the critical temperature and the SEM photography. Then, the critical temperatures of two samples were about 88 K, but the cross section of sample using ICP method was shaper than that using the wet etching method. ICP method can be used as a good etching technique process for patterning of YBaCuO superconductor.

BCl₃및 BCl₃/Ar 고밀도 유도결합 플라즈마를 이용한 GaAs와 AlGaS 반도체 소자의 건식식각

임완태,백인규,이제원,조관식,전민현,Lim, Wan-tae,Baek, In-kyoo,Lee, Je-won,Cho, Guan-Sik,Jeon, Min-hyun 한국재료학회 2003 한국재료학회지 Vol.13 No.10

We investigated dry etching of GaAs and AiGaAs in a high density planar inductively coupled plasma system with BCl$_3$and BCl$_3$/Ar gas chemistry. A detailed etch process study of GaAs and ALGaAs was peformed as functions of ICP source power, RIE chuck power and mixing ratio of $BCl_3$ and Ar. Chamber process pressure was fixed at 7.5 mTorr in this study. The ICP source power and RIE chuck power were varied from 0 to 500 W and from 0 to 150 W, respectively. GaAs etch rate increased with the increase of ICP source power and RIE chuck power. It was also found that etch rates of GaAs in $15BCi_3$/5Ar plasmas were relatively high with applied RIE chuck power compared to pure 20 sccm $BCl_3$plasmas. The result was the same as AlGaAs. We expect that high ion-assisted effect in $BCl_3$/Ar plasma increased etch rates of both materials. The GaAs and AlGaAs features etched at 20 sccm $BCl_3$and $15BCl_3$/5Ar with 300 W ICP source power, 100 W RIE chuck power and 7.5 mTorr showed very smooth surfaces(RMS roughness < 2 nm) and excellent sidewall. XPS study on the surfaces of processed GaAs also proved extremely clean surfaces of the materials after dry etching.

Electrical, Luminescent and Structural Properties of Nanopillar GaN/InGaN Multi-Quantum-Well Structures Prepared by Dry Etching

Polyakov, A. Y.,Cho, Han-Su,Yun, Jin-Hyeon,Lee, In-Hwan,Yakimov, E. B.,Smirnov, N. B.,Shcherbachev, K. D. The Electrochemical Society 2016 ECS journal of solid state science and technology Vol.5 No.6

<P>GaN/InGaN multiple quantum well (MQW) structures with undoped n-GaN cap imitating true light emitting diodes were grown on sapphire and converted to deep nanopillar (NP) structures by dry etching beyond the MQW region. Structural measurements, electrical measurements on Schottky diodes, microcathodoluminescence (MCL) spectra measurements indicate a strong relaxation of strain in NP MQWs manifested in the prominent increase of the bowing radius of the structures and in the blueshift of the MQW peak in MCL spectra. Various treatments of the as-etched NP MQWs (annealing at 700 degrees C, etching in KOH, and soaking in (NH4)(2)S) progressively decreased the leakage current of Schottky diodes and increased the MQW MCL peak intensity due to the suppression of the dry-etching damage of the nanopillar sidewalls. (C) 2016 The Electrochemical Society. All rights reserved.</P>

BCl₃ 기반의 혼합가스들을 이용한 InP 고밀도 유도결합 플라즈마 식각

조관식,임완태,백인규,이제원,전민현,Cho, Guan-Sik,Lim, Wan-tae,Baek, In-Kyoo,Lee, Je-won,Jeon, Min-hyun 한국재료학회 2003 한국재료학회지 Vol.13 No.12

We studied InP etching in high density planar inductively coupled $BCl_3$and $BCl_3$/Ar plasmas(PICP). The investigated process parameters were PICP source power, RIE chuck power, chamber pressure and $BCl_3$/Ar gas composition. It was found that increase of PICP source power and RIE chuck power increased etch rate of InP, while that of chamber pressure decreased etch rate. Etched InP surface was clean and smooth (RMS roughness <2 nm) with a moderate etch rate (300-500 $\AA$/min) after the planar $BCl_3$/Ar ICP etching. It may make it possible to open a new regime of InP etching with $CH_4$$H_2$-free plasma chemistry. Some amount of Ar addition (<50%) also improved etch rates of InP, while too much Ar addition reduced etch rates of InP.