• 한국진공학회지
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• 제8권1호
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• pp.20-25
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• 1999

여러 가지 방법의 plasma 표면 처리와 산화 공정이 $SiO_2-Si$(100) 계면에 미치는 물리적 영향을 angle resolved uv-photoelectron spectroscopy(ARUPS)를 이용하여 연구하였다. 표면은 ex situ 방법과 함께 in situ 수소 플라즈마를 이용하여 처리되어 졌으며, 이것은 고진공 고온 열 처리 방법과 비교되어졌다. ARUPS 빛띠 상에 나타난 산화물 가전자 띠에 대한 특징적인 peak 위치는 표면 처리 및 산화 공정 방법에 따라 이동하였다. 이러한 peak의 이동은 Si에서의 띠휨에 의한 것으로 분석되어졌다. 또한 peak 이동의 원인으로 Si-SiO2 계면에 형성된 결점과 표면 처리 공정에 따라 달라지는 표면 거칠기 등을 고려할 수 있었다. 여러 공정에 대한 ARUPS 결과를 비교함으로써 $Si--SiO_2$(계면 결합이 표면 처리 및 산화 방법에 깊이 관련되어 있음을 결론지을 수 있었다. 산소 plasma 공정은 가장 작은 band bending을 보여주었다.

• 한국세라믹학회지
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• 제31권7호
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• pp.753-758
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• 1994

(100) Si and 4$^{\circ}$off (100) Si were oxidized in dry oxygen, and the differences in thermal oxidation behavior and electrical characteristics between two specimens were investigated. Ellipsometer measurements of the oxide thickness produced by oxidation in dry oxygen from 1000 to 120$0^{\circ}C$ showed that the oxidation rates of the 5$^{\circ}$ off (100) Si were more rapid than those of the (100) Si and the differences between them decreased as the oxidation temperature increased. The activation energies based on the parabolic rate constant, B for (100) and 4$^{\circ}$off (100) Si were 25.8, 28.6 kcal/mol and those on the linear rate constant, B/A were 56.8, 54.9 kcal/mol, respectively. Variation of C-V characteristics with the oxidation temperature showed that the flat band voltages were shifted positively and surface state charge densities decreased as the oxidation temperature increased, and the surface state charge density of the 4$^{\circ}$off (100) Si was lower than that of the (100) Si. Also considerable decrease in the density of oxidation induced stacking faults (OSF) for the 4$^{\circ}$off (100) Si was observed through optical microscopy after preferentially etching off the oxide layer.

• 한국결정학회지
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• 제17권2호
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• pp.51-54
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• 2006

BaO layers were formed on the Si(100) surface by thermal evaporation of barium metal with simultaneous oxidation. The atomic structure of BaO layers at the initial stage of the deposition was investigated by the scattering intensity variation of $He^+$ions on time-of-flight (TOF) impact-collision ion scattering (ICISS). The results show that several number of BaO layers are formed on the Si(100) surface with the lattice parameter of bulk phase, and the occupation of oxygen atoms of the BaO layers is on-top site of silicon atoms.

• Applied Science and Convergence Technology
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• 제26권6호
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• pp.174-178
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• 2017

The reactions of thermal hydrogen atoms H(g) with the Ge(100) surface were examined with temperature-programmed desorption (TPD) mass spectrometry. Concomitant $H_2$ and $CH_4$ TPD spectra taken from the H(g)-irradiated Ge(100) surface were distinctly different for low and high H(g) doses/substrate temperatures. Reactions suggested by our data are: (1) adsorbed mono(${\beta}_1$)-/di-hydride(${\beta}_2$)-H(a) formation; (2) H(a)-by-H(g) abstraction; (3) $GeH_3$(a)-by-H(g) abstraction (Ge etching); and (4) hydrogenated amorphous germanium a-Ge:H formation. While all these reactions occur, albeit at higher temperatures, also on Si(100), H(g) absorption by Ge(100) was not detected. This is in contrast to Si(100) which absorbed H(g) readily once the surface roughened on the atomic scale. While this result is rather against expectation from its weaker and longer Ge-Ge bond as well as a larger lattice constant, we attribute the absence of direct H(g) absorption to insufficient atomic-scale surface roughening and to highly efficient subsurface hydrogenation at moderate (>300 K) and low (${\leq}300K$) temperatures, respectively.

• 한국결정성장학회지
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• 제21권4호
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• pp.153-157
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• 2011

Inductively Coupled Plasma(ICP)를 이용하여 다양한 조건으로 표면 처리한 Si(100) 기관 위에 Low Pressure Chemical Vapor Deposition(LPCVD)를 이용하여 Ge 층을 이종접합 성장하고, Ge 층 성장 초기의 표면 상태를 Scanning Electron Microscopy(SEM)을 통해 분석하였다. ICP를 이용하여 표면 처리된 Si(100) 기판 위에 성장된 Ge 층의 경우 ICP 처리하지 않은 시편보다 Ge 성장율이 약 5배 이상 증가되었다. ICP 처리된 시편의 Ge 성장률 증가는 ICP 표면 처리 공정으로 Si 기관 표면에서 떨어져 나간 missing dimer가 Ge adatom들에 핵을 형성할 자리를 제공하여 Ge island의 형성과 융합을 촉진시키는 것으로 사료된다.

• Bulletin of the Korean Chemical Society
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• 제33권3호
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• pp.775-778
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• 2012

The potential energy surfaces of ammonia molecule adsorptions on the symmetrically chlorinated Si(100)-$2{\times}1$ surface were explored with SIMOMM:MP2/6-31G(d). It was found that the initial nucleophilic attack by ammonia nitrogen to the surface Si forms a $S_N2$ type transition state, which eventually leads to an HCl molecular desorption. The second ammonia molecule adsorption requires much less reaction barrier, which can be rationalized by the surface cooperative effect. In general, it was shown that the surface Si-Cl bonds can be easily subjected to the substitution reactions by ammonia molecules yielding symmetric surface Si-$NH_2$ bonds, which can be a good initial template for subsequent surface chemical modifications. The ammonia adsorptions are in general more facile than the corresponding water adsorption, since ammonia is better nucleophile.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2007년도 춘계학술발표회 초록집
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• pp.145-146
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• 2007

Cr-Si-N 박막은 하이브리드 코팅 시스템에 의해 온도와 바이어스의 변화에 따라 증착 되었다. 증착온도 $0{\sim}300^{\circ}C$ 범위에서, 경도와 탄성계수는 이온의 surface mobility의 증가 때문에 향상되었지만 $350^{\circ}C$ 이상의 증착 온도에서는 결정성장 때문에 경도는 다시 감소하였다. 바이어스 $0{\sim}-100V$까지 범위에서는, 경도와 탄성계수는 각각 46GPa, 600GPa의 최대값을 보여주었으며 바이어스 -100V에서 macro-particle과 surface molphology 감소가 발생하였다. 그러나 -100V이상의 바이어스에서 resputtering 현상에 의해 Si 의 양이 감소한다. 증착온도는 Si 함량에 많은 영향을 주지 못한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.25-25
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• 2000

In this talk we discuss the dynamics of hydrogen on the Si(100)-2xl surface. At room temperature the sticking coefficient for molecular hydrogen on this surface is less than 10sup-12. However, hydrogen molecules desorbing from the surface do not have an excess of energy, suggesting at best a small barrier on the exit channel. These observations have led to speculation about the validity of detailed balance in this system. Here we show that this discrepancy can be explained by considering both the surface-molecule co-ordinate and that associated with the Si-Si dimer bond tiltangle. By preparing the surface dimers with a specific tiltangle we demonstrate that the barrier to adsorption is a function of this angle and that the sticking coefficient dramatically increase for certain angles. The adsorption-desopption dynamics can then be described in terms of a common potential energy hypersurface involving both of these co-ordinates. The implications of these observations are also discussed. The dynamics of adsorbed hydrogen atoms on the Si(100) surface is also described. Paired dangling bonds produced following recombinative hydrogen desorption are mobile at elevated temperatures. Pairs of dangling bonds are observed to dissociate, diffuse, and ultimately recombine. At sufficiently elevated temperatures dangling bond exchange reactions are observed. These data are analyzed in terms of an attractive zone and an effective binding interaction between dangling bonds. Insights that this provides into the nature of surface defects and the localized chemistry that occurs on this surface, are also discussed.

• 한국진공학회지
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• 제2권2호
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• pp.161-165
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• 1993

Si(100)와 Si(111) 표면에 에피 성장시킨 Ge의 기하학적, 전기적 구조가 scanning tunneling microscope로 연구되었다. Ge 원자는 scanning tunneling spectroscopy와 bias 전압을 달리한 STM 상에서 Si 원자와 구별되었다. 이것을 이용하여 Ge의 성장 형태를 연구하였다. (2${\times}$1) 재배열 구조를 가진 (100) 표면에서 Ge 성장층은 720K에서 B형의 step edge로부터 주로 성장하였다. (111) 표면에서도 주로 step edge에서 성장하였으며, Ge의 양과 annealing 온도에 따라 (5${\times}$5)와 (7${\times}$7)구조가 보였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2005년도 제29회 학술발표회 초록집
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• pp.63-63
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• 2005