한병국 / 박주부 수상소감

한병국,박주부 고요아침 2019 열린시학 Vol.24 No.4

Avalanche Injection Trapping에 의한 물확산(Water Diffusion)된 산화막의 두께의존성에 관한 연구

한병국 慶山大學校 基礎科學硏究所 1999 基礎科學 Vol.3 No.1

물(water)과 관련된 전자(electron) trapping center의 침투(penetration)가 산화막(oxide) 두께의 변화에 따라 일어나는 조건하에서 열적으로 성장된 건식산화막(dry SiO₂ films) 속으로 물을 확산(diffusion)시켰으며, 이러한 물확산된 산화막에서 전자사태(avalanche electron) 주입량(injection flux)에 의해 부(-)의 산화막전하 Q???? 생성이 관측되었다. 약 150℃에서 물확산의 지배적인 효과는 실온에서 측정된 많은 크기의 trapping center가 생성된다는 것이다. 여러 가지 다른 실험조건 하에서 trapping된 전하밀도의 도심(centroid) x??는 d ?? (산화막두께)<<D(확산길이:diffusion length)일 경우 ∼0.5d??이며, 그리고 N(total trapping center density)??d??>>D일 경우 ∼0.5D이며, N은 d??에 무관하다. 300℃의 물확산된 산화막에서는 D가 매우 증가했음을 보여주고 있다. Water was diffused into very dry thermal SiO₂ films under conditions that the penetration of water related electron trapping centers was of the order of the oxide thickness. In water diffused oxides, production of negative bulk oxide charge Q?? by an avalanche-injected electron flux was observed. The dominant effect of water diffusion at approximately 150℃ is a large density of trapping centers with σ∼10???㎠ at room temperature. For different experimental conditions, we might expect that in films with d??(oxide thickness)<<D(diffusion length), x∼0.5d?? and N??d??. In the other extreme, we might expect that for d??>>D, x∼0.5D and N would be independent of d??. At a sample temperature of 300℃, the water diffusion should have the effect of greatly increasing the water diffusion depth D.

GaAs/AlAs 초격자의 photoluminescence 특성 연구

한병국 慶山大學校 基礎科學硏究所 2000 基礎科學 Vol.4 No.2

MBE(molecular beam epitaxy)를 이용하여 15 monolayer의 두께를 가지는 GaAs/AlAs 초격자를 제작하였다. 특성 연구를 위해 레이저 세기와 온도에 따른 photoluminescence(PL)를 측정하였다. 여기레이저 세기에 따른 PL 강도를 logalithmic plot한 결과 거의 직선으로 나타났으며, 이로부터 상온에서의 재결합과정이 excitomic-like transition에 의한 것으로 분석되었다. 격자온도가 감소할 때, GaAs/AlAs 초격자에서의 Cl-Hl subband 에너지 값은 GaAs 온도 의존성에 따라 증가하였고, 7.2K에서 약 4meV의 차이를 보였다. 이 값은 다른 양질의 양자우물 시료에서 측정된 값과 비슷하게 나타났다. GaAs/AlAs superlattice was grown by molecular beam epitaxy with a thickness of 15 monolayers. We have performed photoluminescence measurement. Measurement were performed as a function of excitation laser power and temperature. The photoluminescence peak intensity as a function of excitation laser power is well described by a straight line on logarithmic plot, indicating that radiative recombination mechanism is excitonic-like transition. Finally, we have showed the temperature dependence of the peak energy of the Hl-Cl transition. When lattice temperature was decreased, the peak energy first increased, following the temperature dependence of the bulk GaAs band gap, and deviated to the lower energy side by about 4meV at 7.2K from extrapolated curve. The observed Stokes shift is in good agreement with previous results on multiple-quantum well sample of the high quality.

Avalanche 주입에 의한 SiO_(2)층 내에 전하 trapping 현상

한병국 慶山大學校 1993 論文集 Vol.11 No.1

We have studied by capacitance and I-V measurements the detail of avalanche injection of electrons into sillicon dioxide. In the process of avalanche injection of electrons into silicon dioxide, besides electron trapping in the bulk of the oxide, there are slow and fast interface states generated. The slow states are donors and positively charged when empty. Together with positive charge in the interface states, they compensate the negative bulk charge to give the turn -around effect. As a function of avalanche fluence F A, the flatband voltage shift did not increase monotonically. Instead, after a maximum voltage shift was reached, the flatband voltage decreased with further injection of electrons. The turn-around effect is observed after 0.1 to 0.15C-cm-2 are injected into an oxide. The effect was explained by the generation of interface states. When heated under (+)5V bias to 100℃, slow states are filled by electrons, whereas for negative bias the states are empty, giving a high positive charge density

Avalanche Electron Trapping에 의한 건식산화막의 두께의존성에 관한 연구

한병국 慶山大學校 1998 論文集 Vol.16 No.1

In MOS (metal-oxide-semiconductor) capacitors with the dry oxide grown thermally, the avalanche electron trapping behavior has been measured as a faction of thickness at 110℃. Flat-band voltage shifts △V_(FB) is dependent on oxide thickness d_(ox)^(2) for dry oxide samples subjected to PMA(postmetalization annealing). This result, and supporting evidence from photo I-V measurments, indicatedthat electron trapping centers were distributed uniformly throughout the oxide layer. For the dry oxides, which were not given PMA, △V_(FB) scaled approximately as d_(ox), and the trapped charge centroid, determined from photo I-V measurements on several 900Å thick samples, was ∼0.32d_(ox).

Avalanche Electron Trapping에 의한 SiO_(2) Layer 및 Si-SiO_(2) Interface 연구

한병국 慶山大學校 1997 論文集 Vol.15 No.1

Determination of the nature and distribution of oxide charge and interface state in MOS capacitors is important to an understanding of oxide charging phenomena. The oxide trap and interface state are studied by injecting carriers into the oxide layer from gate or silicon electrode and by generating carriers by means of ionizing radiation. Generally, the combination of avalanche injection for studding charging the oxide traps and the photo I-V method for determining the trap distribution in the oxide is the most effective way to study bulk oxide traps. In this paper by using the electron avalanche injection, C-V, and photo I-V method, charge trapping phenomenon within the oxide was investigated and then anomalous positive charge buildup from the interface state generation was observed.

GaAs/Al Ga As 다중 양자우물에서 GaAs 기판과 완충층의 Photoreflectance

한병국 慶山大學校 基礎科學硏究所 1997 基礎科學 Vol.1 No.2

Molecular beam epitaxy에 의해 GaAs/Al0.24Ga0.76As 다중 양자우물을 제작하였고, 특성 연구를 위해 PR 측정을 하였다. PR측정결과, 1.42eV 부근의 PR신호는 두개의 신호가 중첩되어 나타났으며, 화학적 에칭으로 GaAs의 기판에 의해 나타나는 3차미분형 신호와 GaAs 완충층에 의해 나타나는 FKO 신호가 중첩되어 나타남을 알 수 있었다. 양자우물에서 나타나는 11H와 11L의 PR측정 에너지값은 각각 1.464eV와 1.475eV였으며, envelope function approximation(EFA)에 의해 계산된 11H와 11L 천이 에너지값과 잘 일치하였다. Photoreflectance(PR) spectroscopy has been used to study GaAs/Al0.24Ga0.76As multiple quantum well grown by molecular beam epitaxy. The PR features near 1.42eV showed overlapping two signals. By chemical etching, we have find that the spectra consist of third derivative functional form associated with the GaAs substrate and Franz-Keldysh oscillation associated with the GaAs buffer. The PR measured transition energies for 11H, 11L are 1.464eV, 1.475eV respectively, which agree with quantum confined energies calculated using the envelope function approximation.

CBE(chemical beam epitaxy)로 성장한 l.lum 파장대를 가지는 InGaAsP의 PR(photoreflectance) 특성연구

한병국,김동열 慶山大學校 1996 論文集 Vol.14 No.1

InGaAsP with 1.1㎛ wavelength was grown by chemical beam epitaxy (CBE). Pure arsine (AsH₃) and phosphine(PH₃) gases were used as group V sources. For the group Ⅲ Sources, TEGa, TMIn were used. InGaAsP epilayer was grown on SI-InP substrate and has a l-㎛ thick. We investigated characteristics of InGaAsP using photoreflectance(PR) and photoluminescence(PL) spectroscopy. From PR measurement, the signal of InGaAsP shows well-defined Franz-Keldysh oscillation (FKO) whose peaks provide energy gap. The energy gap of InGaAsP has been a good agreement with the peak energy of PL.

변조-도핑 AI_0.25Ga_0.75As/In_0.23Ga_0.77As/GaAs 고전자 이동도 트랜지스터 구조의 광변조 분광학

한병국 慶山大學校 基礎科學硏究所 2003 基礎科學 Vol.7 No.1

변조-도핑 Al_0.25Ga_00.75As/In_0.23Ga_0.77As/GaAs 고전자 이동도 트랜지스터 구조에 대해 광변조 분광학(photoreflectance ; PR)을 이용하여 14~300K 온도 변화에 따라서 내부 전기장에 관하여 연구하였다. PR 스펙트라의 모든 온도 영역에서 많은 수의 FKOs가 관측되었다. PR 스펙트라에 대한 빠른 푸리에 변환(fast Fourier transformation ; FFT)을 이용하여 정확한 내부 전기장 값을 구할 수 있었고, FFT 결과 GaAs 완충층의 무거운 정공과 가벼운 정공에 해당되는 두 개의 우세한 피크를 얻을 수 있었다. Photoreflectance spectroscopy of modulation-doped Al_0.25Ga_0.75As/In_0.23Ga_0.77As/GaAs PHEMTs has been measured in temperature range from 14 to 300K. The PR spectra exhibit many Franz-Keldysh oscillations above the band-gap energy of GaAs, indicating the strong built-in electric filed in PHEMTs. In order to determine the accurate built-in electric field, we have applied the fast Fourier transformation(FFT) on PR spectra of PHEMTs sample, The FFT spectra exhibit two dominant peaks that correspond to the heavy and light-holes of GaAs buffer layer.

5가 이온주입에 의해 형성된 ?? 층의 불순물 활성화 연구

문영희,이동건,배인호,김말문,한병국 嶺南大學校 基礎科學硏究所 1995 基礎科學硏究 Vol.15 No.-

Ion implantation was used to form shallow ?? junction in silicon substrate, Czochralski-grown(100) silicon wafers, 5~9 Ω㎝ p-type, were implanted with arsenic and phosphorous at room temperature. Arsenic and phosphorus depth profiles were measured by secondary ion mass spectroscopy(SIMS). Atomic distribution of arsenic and phosphorus in samples could be analysised by comparison of the SIMS prlfiles with computer simulations using the SUPREM Ⅳ program. Peak position of the arsenic profile are about 440 A in depth at 60 keV. And that of the phosphorus profile is about 1100 A in depth at 85 keV. We have measured the behavior of electrical properties - (SRP)Spread sheet resistivity, Hall mobility. sheet resistivity and Sheet carrier concentration - vs annealing temperature as well as lattice recovery of As? and p? implanted silicon samples. In the cases of arsenic and phosphorus implanted samples, increasing of Hall mobility at 500 ~ 700 ℃ annealing temperature was shown recrystallization process of implanted layer.