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Surface Reactions of Atomic Hydrogen with Ge(100) in Comparison with Si(100)
조삼근 한국진공학회 2017 Applied Science and Convergence Technology Vol.26 No.6
The reactions of thermal hydrogen atoms H(g) with the Ge(100) surface were examined with temperatureprogrammed desorption (TPD) mass spectrometry. Concomitant H2 and CH4 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(β1)-/di-hydride(β2)-H(a) formation; (2) H(a)-by-H(g) abstraction; (3) GeH3(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 (≤300 K) temperatures, respectively.
Si(100)에 주입된 불활성 기체 이온들의 방출 특성
조삼근,Jo Sam K. 한국진공학회 2006 Applied Science and Convergence Technology Vol.15 No.1
Si(100)에 주입된 불활성 기체 이온들의 열적 방출 특성을 열탈착(temperature-programmed desorption; TPD) 질량분석법으로 고찰하였다. 약 400K의 표면 온도 조건에서 1keV 비온빔에 시료를 노출시켜 주었을 때, He은 $500\~1100 K$의 넓은 온도 범위에서 Si(100)결정 밖으로 분출되어 나온 반면, Ne, Ar, 및 Kr은 각각 810, 860, 875 K 근처에서 매우 좁은 온도 범위에서 TPD 피크를 나타내며 급격하게 방출되었다. He+ 이온으로 처리된 Si(100)은 표면 원자 구조의 손상이 상대적으로 최소한으로 일어났지만, $Ne^+,\;Ar^+,\;Kr^+$ 등의 이온들로 처리된 경우는 질량이 클수록 표면이 원자 스케일로 더 심하게 손상되었음이 수소 흡탈착 분석 결과로 밝혀졌다. 이온빔에 의한 결정 내부의 결함 생성과 관련하여 이러한 실험적 결과가 시사하는 점들을 논의하였다 Thermally-driven effusion of inert gases out from Si(100), into which energetic $\~l keV\;He^+,\;Ne^+,\;A^r+,\;and\;Kr^+ ions$ had been implanted at a moderate substrate temperatures of $\~400 K$, was investigated by means of temperature-programmed desorption (TPD) mass spectrometry. While He effused out broadly over $500\~1,100 K$, Ne, Ar, and Kr effusion occurred sharply at 810, 860, and 875 K, respectively. Hydrogen adsorption/desorption analysis for the ion-treated Si(100) surfaces indicated minimal to severe damage by ions with increasing mass from He to Kr. Implications of these results in light of literature reports are discussed.
Preparation and Stability of Silyl Adlayers on 2×1-Reconstructed and Modified Si(100) Surfaces
조삼근,Jo, Sam-K. The Korean Vacuum Society 2009 Applied Science and Convergence Technology Vol.18 No.1
Saturation-coverage silyl, $-SiH_3(a)$, overlayers were prepared from $Si_2H_6$ adsorption on three comparative surfaces: clean unmodified; D-precovered; and atomically roughened Si(100). Together with its precursor-mediated adsorption behavior, the surface reactivity of $Si_2H_6$ was found to be the highest on the unmodified Si(100)-$2{\times}1$ surface. This was correlated with its dissociative adsorption mechanism, in which both the $H_3Si-SiH_3$ bond scission and the dual surface $Si-SiH_3(a)$ bond formation require a surface dangling bond 'pair'. The unusually high thermal stability of $-SiH_3(a)$ on the unmodified surface was ascribed to a nearly close-packed $-SiH_3(a)$ coverage of ${\sim}0.9$ monolayer and the consequent lack of dangling bonds on the silyl-packed surface. 깨끗한 Si(100)-$2{\times}1$, D를 먼저 흡착시킨 Si(100)-$2{\times}1$, 그리고 이온 빔에 의해 원자 수준으로 거칠어진 Si(100) 등의 세 가지 표면에 각각 $Si_2H_6$의 흡착시켜 포화 실릴($-SiH_3(a)$) 흡착층을 형성시키고 실험적으로 비교 고찰하였다 전구체 흡착 거동(기작)과 함께 $Si_2H_6$의 표면 분해(화학)흡착 반응성은 개질을 시켜주지 않은 깨끗한 Si(100)-$2{\times}l$ 표면에서 가장 크게 나타났다. 이 결과는 화학흡착 반응 즉, $H_3Si-SiH_3$ 결합 분해와 두 개의 Si-$SiH_6(a)$ 표면결합 형성이 표면의 Dangling Bond Pair 상에서 동시적으로(Concertedly) 일어나는 $Si_2H_6$의 분해흡착 기작으로 설명될 수 있었다. 또한 Si(100)-$2{\times}l$ 표면에 흡착된 $-SiH_3(a)$의 매우 논은 열적 안정성은 ${\sim}0.9\;ML$나 되는 표면 덮힘도와 함께 실릴기로 조밀하게 흡착된 표면에 Dangling Bond가 존재하지 않는 것에 의한 것으로 밝혀졌다.
Preparation and Stability of Silyl Adlayers on 2×1-Reconstructedand Modified Si(100) Surfaces
조삼근 한국진공학회 2009 Applied Science and Convergence Technology Vol.18 No.1
Saturation-coverage silyl, -SiH₃(a), overlayers were prepared from Si2H6 adsorption on three comparative surfaces: clean unmodified; D-precovered; and atomically roughened Si(100). Together with its precursor-mediated adsorption behavior, the surface reactivity of Si₂H6 was found to be the highest on the unmodified Si(100)-2×1 surface. This was correlated with its dissociative adsorption mechanism, in which both the H3Si-SiH3 bond scission and the dual surface Si-SiH₃(a) bond formation require a surface dangling bond ‘pair’. The unusually high thermal stability of -SiH₃(a) on the unmodified surface was ascribed to a nearly close- packed -SiH₃(a) coverage of ~0.9 monolayer and the consequent lack of dangling bonds on the silyl-packed surface.
Preparation and Stability of Silyl Adlayers on 2×1-Reconstructed and Modified Si(100) Surfaces
Sam K. Jo(조삼근) 한국진공학회(ASCT) 2009 Applied Science and Convergence Technology Vol.18 No.1
깨끗한 Si(100)-2×1, D를 먼저 흡착시킨 Si(100)-2×1, 그리고 이온 빔에 의해 원자 수준으로 거칠어진 Si(100) 등의 세 가지 표면에 각각 Si₂H?의 흡착시켜 포화 실릴(-SiH₃(a)) 흡착층을 형성시키고 실험적으로 비교 고찰하였다. 전구체 흡착 거동(기작)과 함께 Si₂H?의 표면 분해(화학)흡착 반응성은 개질을 시켜주지 않은 깨끗한 Si(100)-2×1 표면에서 가장 크게 나타났다. 이 결과는 화학흡착 반응 즉, H₃Si-SiH₃ 결합 분해와 두 개의 Si-SiH₃(a) 표면결합 형성이 표면의 Dangling Bond Pair상에서 동시적으로(Concertedly) 일어나는 Si2H6의 분해흡착 기작으로 설명될 수 있었다. 또한 Si(100)-2×1 표면에 흡착된-SiH₃(a)의 매우 높은 열적 안정성은 ~0.9 ML나 되는 표면 덮힘도와 함께 실릴기로 조밀하게 흡착된 표면에 Dangling Bond가 존재하지 않는 것에 의한 것으로 밝혀졌다. Saturation-coverage silyl, -SiH₃(a), overlayers were prepared from Si₂H? adsorption on three comparative surfaces: clean unmodified; D-precovered; and atomically roughened Si(100). Together with its precursor-mediated adsorption behavior, the surface reactivity of Si₂H? was found to be the highest on the unmodified Si(100)-2×1 surface. This was correlated with its dissociative adsorption mechanism, in which both the H3Si-SiH₃ bond scission and the dual surface Si-SiH₃(a) bond formation require a surface dangling bond ‘pair’. The unusually high thermal stability of -SiH₃(a) on the unmodified surface was ascribed to a nearly closepacked -SiH₃(a) coverage of ~0.9 monolayer and the consequent lack of dangling bonds on the silyl-packed surface.