In_0.5(Ga_1-xAl_x)_0.5P/GaAs 이중 이종접합 구조의 Contactless Electroreflectance에 관한 연구

김정화,조현준,배인호,Kim, Jeong-Hwa,Jo, Hyun-Jun,Bae, In-Ho 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.2

Metal-organic chemical vapour deposition (MOCVD)법으로 성장된 $In_{0.5}(Ga_{1-x}Al_x)_{0.5}P$/GaAs 이중 이종접합 구조의 특성을 contactless electroreflectance (CER) 분광법으로 조사하였다. CER 측정은 변조전압($V_{ac}$), 온도 및 dc 바이어스 전압($V_{bias}$)의 함수로 수행하였다. 상온에서는 5개의 신호가 관측되었는데, 이 신호들은 각각 GaAs, $In_{0.5}Ga_{0.5}P$, $In_{0.5}(Ga_{0.73}Al_{0.27})_{0.5}P$, $In_{0.5}(Ga_{0.5}Al_{0.5})_{0.5}P$ 및 $In_{0.5}(Ga_{0.2}Al_{0.8})_{0.5}P$ 전이에 관련된 것이다. CER 스펙트럼의 온도 의존성으로부터 Varshni 계수 및 평탄인 자를 구하였다. 그리고 인가전압에 따른 신호의 진폭은 순방향 바이어스 전압 인가시 점차로 감소하나, 역방향 바이어스 전압 인가시에는 반대의 경향을 보였다. We have investigated the contactless electroreflectance (CER) properties of $In_{0.5}(Ga_{1-x}Al_x)_{0.5}P$/GaAs double heterostructures grown by metal-organic chemical vapour deposition (MOCVD). The CER measurements on the sample were studied as a function of temperature, modulation voltage ($V_{ac}$), and dc bias voltage ($V_{bias}$). Five signals observed at room temperature are related to the GaAs, $In_{0.5}Ga_{0.5}P$, $In_{0.5}(Ga_{0.73}Al_{0.27})_{0.5}P$, $In_{0.5}(Ga_{0.5}Al_{0.5})_{0.5}P$, and $In_{0.5}(Ga_{0.2}Al_{0.8})_{0.5}P$ transitions, respectively. From the temperature dependence of CER spectrum, the Varshni coefficients and broadening parameters were determined and discussed. In addition, we found that the behavior of the CER amplitude for the reverse bias is larger than that of the forward.

Pyrochlore형 화합물 $In_2(Ti_{1.7}Zn_{0.3})O_{0.67}$과 $In_2(Ti_{1.7}Mg_{0.3})O_{6.7}$에서의 변조구조 관찰

이확주,박현민,조양구,류현,남산,Lee, Hwack-Joo,Park, Hyun-Min,Cho, Yang-Koo,Ryu, Hyun,Nahm, Sahn,Bando, Y. 한국현미경학회 1999 Applied microscopy Vol.29 No.4

Pyrochlore 구조를 갖는 $Lu_2Ti_2O_7$와 그와 유사한 구조를 갖는 화합물, $In_2(Ti_{1.7}Zn_{0.3})O_{6.7}$와 $In_2(Ti_{1.7}Mg_{0.3})O_{6.7}$에 대한 미세구조 관찰을 200kV에서 작동되는 HRTEM을 이용하여 관찰하였다. 두 화합물에서는 변조구조가 관찰되었으나 pyrochlore구조인 $Lu_2Ti_2O_7$에서는 관찰되지 않았다. 전자회절패턴 분석에서는 변조구조는 incommensurate이고 [220] 방향으로 sublattice의 2.69배로 그 주기가 0.953 nm인 초격자가 관찰되었다. 고분해능 격자상에서는 sublattice의 2배 또는 3배의 초격자들로 조합되며 평균적으로 2.7배로 그 주기가 0.967 nm가 되는 초격자상이 관찰되었다. 두 화합물의 결정구조는 입방정 pyrochlore 구조와 아주 유사하나 입방정 축은 $90^{\circ}$에서 약간 벗어난 구조를 갖는다. 변조구조는 전자빔에 의하여 점차적으로 변조구조가 없는 구조로 비가역적으로 변환된다. Microstructural observations on the pyrochlore-type $Lu_2Ti_2O_7$ and the similar type of compounds, $In_2(Ti_{1.7}Zn_{0.3})O_{6.7}$ and $In_2(Ti_{1.7}Mg_{0.3})O_{6.7}$ which were made by the isothermal heat-treatment at 1623K for 18 days in Pt tube, were carried out using a top-entry HRTEM working at 200 kV. The modulated structures were found in both compounds, however, not in $Lu_2Ti_2O_7$. From the electron diffraction pattern analysis, the modulated superlattices are incommensurate and are 2.69 times of sublattices along (220) direction. The high resolution TEM images have shown that the superlattices consist of alternate superlattices which are composed of two or three sublattices, resulting in the average of 2.7 times of sublattices in accordance with the analysis of electron diffraction patterns. The crystal structures of both compounds are found to quite similar to those of pyrochlore, however the evidence that the cubic axes are slightly deviated from right angle. The modulated structure has gradually changed to the unmodulated structure induced by electron irradiation.

In0.5(Ga1-xAlx)0.5P/GaAs 이중 이종접합 구조의 Contactless Electroreflectance에 관한 연구

김정화,조현준,배인호 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.2

Metal-organic chemical vapour deposition (MOCVD)법으로 성장된 In0.5(Ga1-xAlx)0.5P/GaAs 이중 이종접합 구조의 특성을 contactless electroreflectance (CER) 분광법으로 조사하였다. CER 측정은 변조전압(Vac), 온도 및 dc 바이어스 전압(Vbias)의 함수로 수행하였다. 상온에서는 5개의 신호가 관측되었는데, 이 신호들은 각각 GaAs, In0.5Ga0.5P, In0.5(Ga0.73Al0.27)0.5P, In0.5(Ga0.5Al0.5)0.5P 및 In0.5(Ga0.2Al0.8)0.5P 전이에 관련된 것이다. CER 스펙트럼의 온도 의존성으로부터 Varshni 계수 및 평탄인자를 구하였다. 그리고 인가전압에 따른 신호의 진폭은 순방향 바이어스 전압 인가시 점차로 감소하나, 역방향 바이어스 전압 인가시에는 반대의 경향을 보였다. We have investigated the contactless electroreflectance (CER) properties of In0.5(Ga1-xAlx)0.5P/ GaAs double heterostructures grown by metal-organic chemical vapour deposition (MOCVD). The CER measurements on the sample were studied as a function of temperature, modulation voltage (Vac), and dc bias voltage (Vbias). Five signals observed at room temperature are related to the GaAs, In0.5Ga0.5P, In0.5(Ga0.73Al0.27)0.5P, In0.5(Ga0.5Al0.5)0.5P, and In0.5(Ga0.2Al0.8)0.5P transitions, respectively. From the temperature dependence of CER spectrum, the Varshni coefficients and broadening parameters were determined and discussed. In addition, we found that the behavior of the CER amplitude for the reverse bias is larger than that of the forward bias.

HRTEM에 의한 pseudo-brookite 형 화합물$(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$에서의 변조구조 관찰

이확주,박현민,조양구,류현,남산,Lee, Hwack-Joo,Park, Hyun-Min,Cho, Yang-Koo,Ryu, Hyun,Nahm, Sahn,Bando, Y. 한국현미경학회 1999 Applied microscopy Vol.29 No.1

Pseudo-brookite 구조의 $MgTi_2O_5$와 이와 유사한 구조를 갖는 $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$에 관한 미세구조를 200kV에서 작동되는 고분해능 투과전자현미경을 사용하여 관찰하였다. 변조구조는 $MgTi_2O_5$에서는 발견되지 않았으나, $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$에서는 복잡한 구조가 발견되었다. $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$ 구조의 전자회절패턴은 $MgTi_2O_5$와 fundamental 회절점들은 유사하나 4가지 형태의 초격자 회절점이 더 존재하였다. 변조구조의 주기는 [220] 방향으로 3.63nm, 0.79nm, 그러고 0.64 nm를 이루고 [420] 방향으로는 0.81nm를 이룬다. 미세구조 관찰중 전자빔에 의하여 상전이가 야기되어 변조된 구조에서 좀 더 단순화된 변조없는 구조로 가역적으로 전환한다. 가해지는 전자빔에 의한 손상기구는 ledge 구조의 kink에서 void가 형성되어 작은 결정들로 갈라지고 손상이 커지면, 최종적으로 결정성을 잃게 된다. Microstructural observations on the pseudo-brookite $MgTi_2O_5$ and the similar type of $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$ were carried out using a top-entry HRTEM working at 200 kV. The modulated structures were found in $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$, however, not in $MgTi_2O_5$. The electron diffraction patterns of sublattice in $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$ are quite similar to those of pseudo-brookite $MgTi_2O_5$. but the complicated superlattice reflections are present in the diffraction patterns. Four types of modulations have been found. The periodicities for the modulated structure are found to be 3.63 nm, 0.79 nm and 0.64 nm along [220] direction, and 0.81 nm along [420] direction. The phase transition from the modulated structure to the unmodulated one was also observed in situ due to the electron beam irradiation reversibly. Further damage by the electron beam made the crystal to be fragmented into many small crystals with the formation of the voids at the kinks in ledged structure of the surface. The anisotropic arrangements of In and O atoms in $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$ might cause the compound to be unstable under the electron beam.

Comparative Study of Atomic-Layer-Deposited Stacked (HfO₂/Al₂O₃) and Nanolaminated (HfAlO_<i>x</i>) Dielectrics on In_0.53Ga_0.47As

Mahata, Chandreswar,Byun, Young-Chul,An, Chee-Hong,Choi, Sungho,An, Youngseo,Kim, Hyoungsub American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.10

<P>The high-k gate dielectric structures in stacked (HfO<SUB>2</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB>) and nanolaminated (HfAlO<SUB><I>x</I></SUB>) forms with a similar apparent accumulation capacitance were atomic-layer-deposited on n-type In<SUB>0.53</SUB>Ga<SUB>0.47</SUB>As substrates, and their electrical properties were investigated in comparison with a single-layered HfO<SUB>2</SUB> film. Al-oxide interface passivation in both forms proved to be effective in preventing a significant In incorporation in the high-<I>k</I> film and reducing the interface state density. The measured valence band spectra in combination with the reflection electron energy loss spectra were used to extract the energy band parameters of various dielectric structures on In<SUB>0.53</SUB>Ga<SUB>0.47</SUB>As. A further decrease in the interface state density was achieved in the stacked structure than in the nanolaminated structure. However, in terms of the other electrical properties, the nanolaminated sample exhibited better characteristics than the stacked sample, with a smaller border trap density and lower leakage current under substrate injection conditions with and without voltage stressing.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-10/am400368x/production/images/medium/am-2013-00368x_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am400368x'>ACS Electronic Supporting Info</A></P>

In0.49Ga0.51P/GaAs 이종접합 구조의 표면 광전압 특성

김정화,김인수,배인호 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.5

Metal-organic chemical vapour deposition (MOCVD) 법으로 성장된 In0.49Ga0.51P/GaAs 이종접합 구조의 특성을 표면 광전압(surface photovoltage; SPV) 분광법으로 조사하였다. SPV 측정은 입사광의 세기, 변조 주파수, 온도의 함수로 수행하였다. 상온에서 시료의 띠간격 에너지(band gap energy)는 GaAs와 In0.49Ga0.51P는 각각 1.400 및 1.893 eV이었다. 광세기를 증가시킴에 따라 SPV 크기는 증가하는 반면에, 변조 주파수를 증가시킴에 따라 SPV 크기는 감소하였다. 그리고 SPV 스펙트럼의 온도 의존성으로부터 GaAs와 In0.49Ga0.51P의 띠간격 에너지의 변화를 Varshni 및 Bose-Einstein 표현에 의해 분석하였다. We report the surface photovoltage (SPV) properties of In0.49Ga0.51P/GaAs heterostructure grown by metal-organic chemical vapour deposition (MOCVD). The SPV measurements were studied as a function of modulation beam intensity, modulation frequency and temperature. From a line shape analysis of room temperature derivative surface photovoltage (DSPV) spectrum, the band gap energies for GaAs and In0.49Ga0.51P transitions were 1.400 and 1.893 eV respectively. The surface photovoltage (SPV) increases with increasing the light intensity and temperature, whereas the SPV decreases with increasing the modulation frequency. From the temperature variation of the energy gaps, we have analysis by both Varshni and Bose-Einstein type expressions.

In_0.49Ga_0.51P/GaAs 이종접합 구조의 표면 광전압 특성

김정화,김인수,배인호,Kim, Jeong-Hwa,Kim, In-Soo,Bae, In-Ho 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.5

Metal-organic chemical vapour deposition (MOCVD) 법으로 성장된 $In_{0.49}Ga_{0.51}P$/GaAs 이종접합 구조의 특성을 표면 광전압(surface photovoltage; SPV) 분광법으로 조사하였다. SPV 측정은 입사광의 세기, 변조 주파수, 온도의 함수로 수행하였다. 상온에서 시료의 띠간격 에너지(band gap energy)는 GaAs와 $In_{0.49}Ga_{0.51}P$는 각각 1.400 및 1.893 eV이었다. 광세기를 증가시킴에 따라 SPV 크기는 증가하는 반면에, 변조 주파수를 증가시킴에 따라 SPV 크기는 감소하였다. 그리고 SPV 스펙트럼의 온도 의존성으로부터 GaAs와 $In_{0.49}Ga_{0.51}P$의 띠간격 에너지의 변화를 Varshni 및 Bose-Einstein 표현에 의해 분석하였다. We report the surface photovoltage (SPV) properties of $In_{0.49}Ga_{0.51}P$/GaAs heterostructure grown by metal-organic chemical vapour deposition (MOCVD). The SPV measurements were studied as a function of modulation beam intensity, modulation frequency and temperature. From a line shape analysis of room temperature derivative surface photovoltage (DSPV) spectrum, the band gap energies for GaAs and $In_{0.49}Ga_{0.51}P$ transitions were 1.400 and 1.893 eV respectively. The surface photovoltage (SPV) increases with increasing the light intensity and temperature, whereas the SPV decreases with increasing the modulation frequency. From the temperature variation of the energy gaps, we have analysis by both Varshni and Bose-Einstein type expressions.

Bi-Sb-Te계 합금의 열전물성에 대한 Cu 및 In 첨가 영향

조현준,김현식,김상일 대한금속·재료학회 2019 대한금속·재료학회지 Vol.57 No.10

Herein we report the effect of Cu/In doping on the electronic and thermal transport properties of Bi-Sb-Te thermoelectric alloys. To closely examine the role of each doping element when incorporated in a Bi0.4Sb1.6Te3 alloy, different groups of samples were prepared and characterized, including undoped Bi0.4Sb1.6Te3, In single-doped samples and In and Cu doped ones. It was observed that Cu and In had different impacts on the thermoelectric properties of the Bi0.4Sb1.6Te3. For example, the Hall carrier concentration of Bi0.4Sb1.6Te3 was increased by Cu doping and decreased by In doping while maintaining Hall mobility, which suggests that the physical parameters related to the thermoelectric transport can be carefully controlled by doping with Cu and In. In addition, we found that the electronic structure of Bi0.4Sb1.6Te3 can be modified by Cu/In doping. The density of states effective mass (m * ) value of the Cu-doped sample (1.09 m0) was increased. However, the m * of the In-doped sample (0.85 m0) was decreased compared to the pristine sample (0.97 m0). Cu single-doped Bi0.4Sb1.6Te3 exhibited the maximum thermoelectric figure-of-merit because of the complexity of substitutional doping on Bi/Sb sites. Our results indicate that to enhance the performance of thermoelectric materials by doping with more than one element a well-designed doping strategy is required.

광전류분광법에 의한 In_{(0.5)Ga_(1-x)Al_x)}_0.5P/GaAs 이중 이종접합 구조의 특성

김정화,김근형,이승준,김종수,배인호 한국물리학회 2011 새물리 Vol.61 No.2

We have investigated the photocurrent (PC) of In_{(0.5)Ga_(1-x)Al_x)}_0.5P/GaAs double heterostructures grown by using metal-organic chemical vapor deposition (MOCVD). The PC measurements were studied as a function of the light intensity, temperature and external voltage(Vbias). At room temperature, we observed five different transitions, which were related to the band-gap energies for GaAs, In_(0.5)Ga_(0.5)P, In_(0.5)(Ga_(0.73)Al-(0.27)_0.5P,In_0.5{(Ga_(0.5)Al_(0.5)}_0.5P and In_(0.5){(Ga_(0.2)Al_(0.8)}_0.5P , respectively. The PC intensity increased with increasing light intensity, dc bias voltage and temperature. We also used both Varshni and Bose-Einstein type expressions temperature variation of the energy gaps. We found that the PC intensity with applied voltage was much larger for forward bias than for the reverse bias, which might be due to a reduction of the space charge width.

태양광 접속함 정션박스 모듈 적용을 위한 Sn-3.0Ag-0.5Cu 및Sn-1.0Ag-0.7Cu-1.6Bi-0.2In 솔더링의 공정최적화

이병석,오철민,곽현,김태우,윤희복,윤정원 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.3

The soldering property of Pb-containing solder(Sn-Pb) and Pb-free solders(Sn-3.0Ag-0.5Cu and Sn-1.0Ag- 0.7Cu-1.6Bi-0.2In) for solar combiner box module was compared. The solar combiner box module was composed of voltage and current detecting modules, diode modules, and other modules. In this study, solder paste printability, printing shape inspection, solder joint property, X-ray inspection, and shear force measurements were conducted. For optimization of Pb-free soldering process, step 1 and 2 were divided. In the step 1 process, the printability of Pb-containing and Pbfree solder alloys were estimated by using printing inspector. Then, the relationship between void percentages and shear force has been estimated. Overall, the property of Pb-containing solder was better than two Pb-free solders. In the step 2 process, the property of reflow soldering for the Pb-free solders was evaluated with different reflow peak temperatures. As the peak temperature of the reflow process gradually increased, the void percentage decreased by 2 to 4%, but the shear force did not significantly depend on the reflow peak temperature by a deviation of about 0.5 kgf. Among different surface finishes on PCB, ENIG surface finish was better than OSP and Pb-free solder surface finishes in terms of shear force. In the thermal shock reliability test of the solar combiner box module with a Pb-free solder and OSP surface finish,the change rate of electrical property of the module was almost unchanged within a 0.3% range and the module had a relatively good electrical property after 500 thermal shock cycles. 본 연구에서는 태양광 접속함 모듈 적용을 위한 유연 솔더(Sn-Pb) 및 무연 솔더(Sn-3.0Ag-0.5Cu 및 Sn-1.0Ag- 0.7Cu-1.6Bi-0.2In)의 특성을 비교 평가하였다. 접속함 내에는 전압 및 전류 검출용 모듈, 고내압용 다이오드가 실장된 정류모듈 등 다양한 모듈이 내장되어있다. 본 연구에서는 솔더링특성, 인쇄성, 솔더형상 검사, X-ray를 이용한 솔더 내 void 검사 및 접합강도를 측정하였고, 무연 솔더 합금의 공정최적화는 step 1과 step 2로 구분하여 검토를 실시하였다. Step 1 은 유연 솔더와 무연 솔더 페이스트 인쇄 검사 시험을 1차와 2차로 나누어 실험을 진행하였고 printability는 void 함량 및접합강도의 상관관계로 검토하였다. 전체적으로 유연 솔더의 특성은 무연 솔더에 비하여 상대적으로 우수하였다. Step 2 는 리플로우 공정의 최고점 온도 변화에 따른 접합부 특성 변화를 관찰하였다. 리플로우 최고 온도가 증가할수록 접합부내의 void 함량이 2~4% 정도 감소하였고, 접합강도는 약 0.5 kgf 범위내에서 큰 차이 없이 나타났다. 기판 표면처리종류에 있어서는 ENIG 표면처리가 OSP 및 Pb-free 솔더 표면처리보다 우수한 접합강도를 나타내었다. 1종류의 무연솔더와OSP 표면처리로 접합된 태양광 접속함 모듈의 500 싸이클 열충격 신뢰성시험 전후에 전기적 특성변화는 0.3% 내의 범위에서 안정적으로 작동함을 확인하였다.