Si 이 첨가된 Al0.33Ga0.67As 에서의 Electroreflectance 에 관한 연구

김근형,김동렬,김종수,김인수,배인호,한병국 ( Geun Hyoung Kim,Dong Lyeul Kim,Jong Su Kim,In Soo Kim,In Ho Bae,Byung Kuk Han ) 한국전기전자재료학회 1997 전기전자재료학회논문지 Vol.10 No.7

Al0.24Ga0.76As / GaAs 에피층에서의 표면 광전압에 관한 연구

유재인(Jae-In Yu),김도균(Do-Kjun Kim),김근형(Geun-Hyoung Kim),배인호(In-Ho Bae),김인수(In-Soo Kim),한병국(Byung-Kuk Han) 한국진공학회(ASCT) 2000 Applied Science and Convergence Technology Vol.9 No.2

Molecular beam epitaxy(MBE)로 성장시킨 Al_(0.24)Ga_(0.76)As/GaAs 에피층 구조의 표면 광전압을 측정하였다. 측정된 신호로부터 구한 Al_(0.24)Ga_(0.76)As 에피층, GaAs 기판 그리고 GaAs 완충층의 밴드갭 에너지는 각각 1.72, 1.40그리고 1.42 eV이다. 이는 photoreflectance(PR) 측정 결과와 잘 일치하였다. 그리고 Al_(0.24)Ga_(0.76)As에피층이 GaAs 기판의 표면 광전압 세기 보다 약 3배 정도 작게 나타났는데, 이는 캐리어의 이동도 차이로 나타나는 현상으로 해석된다. 또한 표면 광전압의 온도 의존성으로부터 Varshni 식의 계수들을 구하였다. We measured surface photovoltage (SPV) of Al_(0.24)Ga_(0.76)As/GaAs epilayer grown by molecular beam epitaxy (MBE). The band gap energies of Al_(0.24)Ga_(0.76)As epilayer, GaAs substrate and buffer layer obtained from SPY signals are 1.70, 1.40 and 1.42 eV, respectively. There results are in good agreements with photoreflectance (PR) measurement. The measured SPY intensity of GaAs substrate is three times larger than Al_(0.24)Ga_(0.76)Asepilayer by carrier mobility difference. The parameters of Varshni equation were determined from the SPY spectra as a function of temperature.

Photoreflectance 측정에 의한 InxGa₁-xAs(0.03≤X≤0.11) 에피층의 특성 연구

김인수(In-Soo Kim),손정식(Jeoog-Sik Son),이철욱(Cheul-Wook Lee),배인호(In-Ho Bae),임재영(Jae-Youog Leem),한병국(Byung-Kuk Han),신영남(Young-Nam Shin) 한국진공학회(ASCT) 1998 Applied Science and Convergence Technology Vol.7 No.4

Molecular Beam Epitaxy(MBE)법으로 성장된 In_xGa_(1-x)As/GaAs 에피층에 대해 photoreflectance (PR)실험을 통해 특성을 조사하였다. PR 측정결과 성장된 In_xGa_(1-x)As 에피층의 띠간격 에너지(E。) 신호가 시료의 변형(strain)에 의해 heavy-hole(E。(HH))과 light-hole(E。(LH))로 분리되어 관측되었다. 에피층의 조성과 변형은 각각 시료에서의 E。(HH) 및 Eo(HH)와 Eo(LH)신호의 에너지 차이를 이용하여 구하였다. 또 160 K이하의 온도에서는 Eo(LH)의 신호가 사라짐을 볼 수 있었다. Franz-Keldysh oscillation(FKO) 피크로부터 계산되어진 InGaAs/GaAs 계면전장 (E)은 In 조성의 증가에 따라 0.75×10^5 V/㎝에서 2.66×10^5 V/㎝로 증가하였다. In 조성이 x=0.09인 시료에 대한 PR신호의 온도의존성 실험에서 Varshni 계수와 Bose-Einstein 계수들을 각각 구하였다. Photoreflectance (PR) measurents have been performed on In_xGa_(1-x)As/GaAs grown by molecular beam epitaxy (MBE). Bandgap (E。) of In_xGa_(1-x)As epilayer measured from PR was separated as heavy-hole (E。(HH)) and light-hole (E。(LH)) by strain effect. The compositions and the strains of epilayer were obtained from the energy value of E。(HH) and from enegy difference of E。(HH) and E。(LH), respectively. In addition, the PR signal of E。(LH) was diminished below 160 K. The interface electric field (E) of InGaAs/GaAs was increased from 0.75×10^5 V/㎝ to 2.66×10^5 V/㎝ as In composition increased, which was calculated from Franz-Keldysh oscillation (FKO) peaks. As the temperature dependence of the PR signal at x=0.09 sample, we obtained Varshni and Bose-Einstein coefficients.

아르곤 플라즈마로 처리한 n - GaAs의 표면특성에 관한 Photoreflectance 연구

이동율(Dong-Yul Lee),김인수(In-Soo Kim),김동렬(Dong-Lyeul Kim),김근형(Geun-Hyoung Kim),배인호(In-Ho Bae),김규호(Kyoo-Ho Kim),한병국(Byung-Kuk Han) 한국진공학회(ASCT) 1997 Applied Science and Convergence Technology Vol.6 No.4

Power를 40 W로 고정하고 시간을 5~120초간 변화시켜 아르콘 플라즈마로 처리시킨 n-GaAs(100)의 특성을 photoreflectance(PR) 측정으로 조사하였다. 아르곤 플라즈마 처리시간을 증가시킴에 따라 E。 피크의 세기는 처리시간이 5초일 때 최소로 관측되었으며, 이때 표면전기장(E_S), 순수 캐리어농도(N_D-N_A) 및 표면상태 밀도 (Q_(SS))는 각각 1.05×10^5 V/㎝, 1.31×10^(17) ㎝-³ 및 1.64×10^(-7) C/㎡로 이 값들은 bulk 시료에 비해 약 57.1, 81.4 및 56.9% 감소하였다. 반면에 5초일 때 compensation center 농도(N_A)는 5.57×10^(17) ㎝-³로 최대였다. 그리고 아르곤 플라즈마 처리시 유발된 결함들의 침투깊이는 표면에서 약 450 Å 정도였다. We have investigated the surface characteristics of n-GaAs (100) treated with Ar plasma (40 W, 5~120 sec) by photoreflectance (PR) measurement. With increasing Ar plasma treatment time, the intensity of E。 peak observed to the minimum at 5 sec. The surface electric field (E_S), net carrier concentration (N_D-N_A), and surface state density (Q_(SS)) are 1.05×10^5 V/㎝, 1.31×10^(17) ㎝-³ and 1.64×10^(-7) C/㎡, respectively. These values were about 57.1, 81.4 and 56.9% smaller than those of bulk n-GaAs. On the other hand, the concentration of compensation centers (N_A) was maximum with value of 5.57×10^(17) ㎝-³ at 5 sec. And penetration depth of defects generated after treated with Ar plasma was about 450 Å from surface.

Al0.2Ga0.8As/SI-GaAs 구조의 Photoreflectance 특성

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

Al??Ga??As/GaAs 구조에 대해 photoreflectance(PR) 측정를 수행하였으며, PR 스펙트럼이 GaAs 기판으로부터 근원이되는 두 개의 신호의 중첩으로 되어 있음을 관측하였다. modulation beam power dependence으로부터, GaAs에서 PR신호를 야기시키는 photo-carrier가 계면 부근에서 발생됨이 밝혀졌다. GaAs 기판으로부터의 PR신호가 높은 변조 주파수에서 다른 기여(contribution)와 분리되어 질 수 있음을 증명했으며, 변조 주파수 의존성 측정을 통하여 이러한 것이 photo-carrier의 lifetime의 차로인한 결과로 나타남을 밝혔다. We have performed photoreflectance(PR) measurement for Al0.2Ga0.8As/GaAs structure and have observed that PR spectrum is superposition of two signals which originate from GaAs substrate. From the modulation beam power dependence, we reveal that the photo-carriers, which cause the PR signals from the GaAs, are generated at the vicinity of the interface. We have also demonstrated that PR signals from GaAs substrate can be separated from the other contributions at a high modulation frequency. Through measuring the modulation frequency dependence, we have confirmed that this results from the difference of the lifetimes of photo-carriers.

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.

SiO₂층 속의 이동성 이온의 이동도 측정

金末文,韓炳國 嶺南大學校附設 基礎科學硏究所 1989 基礎科學硏究 Vol.9 No.-

Na?? and K+ ions have been contaminated in thermally grown SiO₂thin film of metal-oxide-silicon structure. The mobilities of the Na+ and K+ ions were determined from the isothermal transient ionic current method measured in temperature ranges 100∼250℃ and 300∼450℃ respectively. For Na ions; μ=3.3x10-⁴exp(-0.49ev/KT)∼7.6x10-³exp(-0.55eV/KT)㎠/V.sec and for K+ ions; μ=4.4x10-³exp(1.03eV/KT)∼4.6x10-³exp(-1.04eV/KT)㎠/V.sec.

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

이온 주입된 실리콘에서 라만 특성 연구

김말문,이동건,문영희,한병국 嶺南大學校 基礎科學硏究所 1994 基礎科學硏究 Vol.14 No.-

Raman characterization measurements are performed in order to study the effects of the furnace annealing and rapid thermal annealing on arsenic implanted silicon wafers. The post-implanted period was followed by thermal isochronal annealing at various temperatures. Special attention has been given to the amorphous/crystal transition occurring at various annealing temperatures. The changes of the dimensions of the microcrystalline regions and the root mean square bond angle deviation of Si-Si bonds in amorphized regions are evaluated.

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.