• Title, Summary, Keyword: Passivation

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Nitric Acid를 이용한 SiNx/SiO2 Double Layer Passivation

  • Choe, Jae-U;Kim, Hyeon-Yeop;Lee, Jun-Sin
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.405-405
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    • 2011
  • 실리콘 질화막(SiNx : H)는 결정질 실리콘 태양전지 제작 공정에서 ARC (Anti Reflection Coating)과 표면 패시베이션의 역할로써 많이 사용되었지만, layer 자체의 quality가 좋지 않기 때문에 최근에는 SiNx/SiO2 이중 layer로 passivation layer를 형성하고 있다. SiO2 layer는 Si substrate를 소스로 하여 성장시키기 때문에 막의 질이 우수하기는 하지만, 막 성장을 위해서 Furnace를 이용해야 하기 때문에, 공정 시간과 공정 비용을 증가시키는 단점이 있다. 본 연구에서는 SiO2 layer를 Furnace가 아닌, 질산(HNO3)을 이용하여SiNx/Thin SiO2 passivation layer 제작하였다. 실험에서는 SiO2 성장을 위해서 질산 용액에 p-type wafer를 dipping하여 시간대 별, SiO2 막의 두께를 관찰하였고, passivation의 효과를 확인하기 위해 lifetime을 측정하였다. 그 결과 SiNx/SiO2 이중 passivation layer는 SiNx 단일 막으로 passivation을 하였을 때보다, lifetime이 10 us 상승했고, 셀 제작시 효율은 약 1.1%, Fill Factor는 약 4% 정도 증가한 것을 확인할 수 있었다.

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A study on wafer surface passivation properties using hydrogenated amorphous silicon thin film (수소화된 비정질 실리콘 박막을 이용한 웨이퍼 패시베이션 특성 연구)

  • Lee, Seungjik;Kim, Kihyung;Oh, Donghae;Ahn, Hwanggi
    • 한국신재생에너지학회:학술대회논문집
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    • pp.46.1-46.1
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    • 2010
  • Surface passivation of crystalline silicon(c-Si) surface with a-Si:H thin films has been investigated by using quasi-steady-state photo conductance(QSSPC) measurements. Analyzing the influence of a-Si:H film thickness, process gas ratio, deposition temperature and post annealing temperature on the passivation properties of c-Si, we optimized the passivation conditions at the substrate temperature of $200-250^{\circ}C$. Best surface passivation has been obtained by post-deposition annealing of a-Si:H film layer. Post annealing around the deposition temperature was sufficient to improve the surface passivation for silicon substrates. We obtained effective carrier lifetimes above 5.5 ms on average.

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Improved Dit between ALD HfAlO Dielectric and InGaAs Substrate Using NH3 Plasma Passivation (InGaAs 위의 NH3 Plasma Passivation을 이용한 ALD HfAlO유전체 계면전하(Dit) 향상)

  • Choi, Jae Sung
    • Journal of the Semiconductor & Display Technology
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    • v.17 no.4
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    • pp.27-31
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    • 2018
  • The effect of $NH_3$ plasma passivation on the chemical and electrical characteristics of ALD HfAlO dielectric on the InGaAs substrate was investigated. The results show that $NH_3$ plasma passivation exhibit better electrical & chemical performance such as much lower leakage current, lower density of interface trap(Dit) level, and low unstable interfacial oxide. $NH_3$ plasma passivation can effectively enhance interfacial characteristics. Therefore $NH_3$ plasma passivation improved the HfAlO dielectric performance on the InGaAs substrate.

Pt-AlGaN/GaN HEMT-based hydrogen gas sensors with and without SiNx post-passivation

  • Vuong, Tuan Anh;Kim, Hyungtak
    • Journal of IKEEE
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    • v.23 no.3
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    • pp.1033-1037
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    • 2019
  • GaN-based sensors have been widely investigated thanks to its potential in detecting the presence of hydrogen. In this study, we fabricated hydrogen gas sensors with AlGaN/GaN heterojunction and investigated how the sensing performance to be affected by SiN surface passivation. The gas sensor employed a high electron mobility transistors (HEMTs) with 30 nm platinum catalyst as a gate to detect the hydrogen presence. SiN layer was deposited by inductively-coupled chemical vapor deposition as post-passivation. The sensors with SiN passivation exhibited hydrogen sensing characteristics with various gas flow rates and concentrations of hydrogen in inert background gas at $200^{\circ}C$ similar to the ones without passivation. Aside from quick response time for both sensors, there are differences in sensitivity and recovery time because of the existence of the passivation layer. The results also confirmed the dependence of sensing performance on gas flow rate and gas concentration.

The Improvement of Display Brightness in LCD-TV Panel through the Optimization of Organic Passivation Process

  • Lee, Yeong-Beom;Lee, Hi-Kuk;Kim, Shi-Yul;Kim, Sang-Soo
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.235-238
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    • 2008
  • We report the improvement in brightness through the optimization of the organic passivation process for fabricating a TFT substrate for LCD-TV panel. In conclusion, the optimization of organic passivation was accomplished with improving over $10\;cd/m^2$ in brightness than that of a conventional organic passivation process.

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A Study on HF Chemical Passivation for Crystalline Silicon Solar Cell Application (결정질 태양전지를 위한 HF 화학 패시베이션 연구)

  • Choi, Jeong-Ho;Roh, Si-Cheol;Yu, Dong-Yeol;Li, Zhen-Hua;Kim, Yeong-Cheol;Seo, Hwa-Il
    • Journal of the Semiconductor & Display Technology
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    • v.10 no.1
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    • pp.51-55
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    • 2011
  • The surface passivation is one of the important methods that can improve the efficiency of solar cells and can be classified into two methods: wet-chemical passivation and film passivation. In this paper, chemical HF treatment were employed for the passivation of n-type silicon wafers and their effects were studied. To investigate film passivation effects, the silicon nitride films were also deposited by PECVD (plasma-enhanced chemical vapor deposition) on n-type silicon wafers treated with chemical HF. The minority carrier lifetime measurements were used for evaluation of the passivation characteristics in the all experiments steps. We confirmed that the minority carrier lifetime was improved with chemical HF treatment due to passivation effects by H-termination.

Factors to Influence Thermal-Cycling Reliability of Passivation Layers in Semiconductor Devices Utilizing Lead-on-Chip (LOC) Die Attach Technique (리드 온 칩 패키징 기술을 이용하여 조립된 반도체 제품에서 패시베이션 박막의 TC 신뢰성에 영향을 미치는 요인들)

  • Lee, Seong-Min;Lee, Seong-Ran
    • Korean Journal of Materials Research
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    • v.19 no.5
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    • pp.288-292
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    • 2009
  • This article shows various factors that influence the thermal-cycling reliability of semiconductor devices utilizing the lead-on-chip (LOC) die attach technique. This work details how the modification of LOC package design as well as the back-grinding and dicing process of semiconductor wafers affect passivation reliability. This work shows that the design of an adhesion tape rather than a plastic package body can play a more important role in determining the passivation reliability. This is due to the fact that the thermal-expansion coefficient of the tape is larger than that of the plastic package body. Present tests also indicate that the ceramic fillers embedded in the plastic package body for mechanical strengthening are not helpful for the improvement of the passivation reliability. Even though the fillers can reduce the thermal-expansion of the plastic package body, microscopic examinations show that they can cause direct damage to the passivation layer. Furthermore, experimental results also illustrate that sawing-induced chipping resulting from the separation of a semiconductor wafer into individual devices might develop into passivation cracks during thermal-cycling. Thus, the proper design of the adhesion tape and the prevention of the sawing-induced chipping should be considered to enhance the passivation reliability in the semiconductor devices using the LOC die attach technique.

A Review on Silicon Oxide Sureface Passivation for High Efficiency Crystalline Silicon Solar Cell (고효율 결정질 실리콘 태양전지 적용을 위한 실리콘 산화막 표면 패시베이션)

  • Jeon, Minhan;Kang, Jiyoon;Balaji, Nagarajan;Park, Cheolmin;Song, Jinsoo;Yi, Junsin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.6
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    • pp.321-326
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    • 2016
  • Minimizing the carrier recombination and electrical loss through surface passivation is required for high efficiency c-Si solar cell. Usually, $SiN_X$, $SiO_X$, $SiON_X$ and $AlO_X$ layers are used as passivation layer in solar cell application. Silicon oxide layer is one of the good passivation layer in Si based solar cell application. It has good selective carrier, low interface state density, good thermal stability and tunneling effect. Recently tunneling based passivation layer is used for high efficiency Si solar cell such as HIT, TOPCon and TRIEX structure. In this paper, we focused on silicon oxide grown by various the method (thermal, wet-chemical, plasma) and passivation effect in c-Si solar cell.

InGaN/GaN Blue LED device 제조시 ALD (Atomic Layer Deposition) 방법으로 증착된 Al2O3 Film의 Passivation 효과

  • Lee, Seong-Gil;Bang, Jin-Bae;Yang, Chung-Mo;Kim, Dong-Seok;Lee, Jeong-Hui
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.211-212
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    • 2010
  • GaN 기반의 상부발광형 LED는 동작되는 동안 생기는 전기적 단락, 그리고 칩 위의 p-형 전극과 n-형 전극 사이에 생기는 누설전류 및 신뢰성 확보를 위하여 칩 표면에 passivation 층을 형성하게 된다. SiO2, Si3N4와 같은 passivation layers는 일반적으로 PECVD (Plasma Enhanced Chemical Vapor Deposition)공정을 이용한다, 하지만 이는 공정 특성상 plasma로 인한 damage가 유발되기 때문에 표면 누설 전류가 증가 한다. 이로 인해 forward voltage와 reverse leakage current의 특성이 저하된다. 본 실험에서는 원자층 단위의 박막 증착으로 인해 PECVD보다 단차 피복성이 매우 우수한 PEALD(Plasma Enhanced Atomic Layer Deposition)공정을 이용하여 Al2O3 passivation layer를 증착한 후, 표면 누설전류와 빛의 출력 특성에 대해서 조사해 보았다. PSS (patterned sapphire substrate) 위에 성장된 LED 에피구조를 사용하였고, TCP(Trancformer Copled Plasma)장비를 사용하여 에칭 공정을 진행하였다. 이때 투명전극을 증착하기 위해 e-beam evaporator를 사용하여 Ni/Au를 각각 $50\;{\AA}$씩 증착한 후 오믹 특성을 향상시키기 위하여 $500^{\circ}C$에서 열처리를 해주었다. 그리고 Ti/Au($300/4000{\AA}$) 메탈을 사용하여 p-전극과 n-전극을 형성하였다. Passivation을 하지 않은 경우에는 reverse leakage current가 -5V 에서 $-1.9{\times}10-8$ A 로 측정되었고, SiO2와 Si3N4을 passivation으로 이용한 경우에는 각각 $8.7{\times}10-9$$-2.2{\times}10-9$로 측정되었다. Fig. 1 에서 보면 알 수 있듯이 5 nm의 Al2O3 film을 passivation layer로 이용할 경우 passivation을 하지 않은 경우를 제외한 다른 passivation 경우보다 reverse leakage current가 약 2 order ($-3.46{\times}10-11$ A) 정도 낮게 측정되었다. 그 이유는 CVD 공정보다 짧은 ALD의 공정시간과 더 낮은 RF Power로 인해 plasma damage를 덜 입게 되어 나타난 것으로 생각된다. Fig. 2 에서는 Al2O3로 passivation을 한 소자의 forward voltage가 SiO2와 Si3N4로 passivation을 한 소자보다 각각 0.07 V와 0.25 V씩 낮아지는 것을 확인할 수 있었다. 또한 Fig. 3 에서는 Al2O3로 passivation을 한 소자의 output power가 SiO2와 Si3N4로 passivation을 한 소자보다 각각 2.7%와 24.6%씩 증가한 것을 볼 수 있다. Output power가 증가된 원인으로는 향상된 forward voltage 및 reverse에서의 leakage 특성과 공기보다 높은 Al2O3의 굴절률이 광출력 효율을 증가시켰기 때문인 것으로 판단된다.

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