• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.397-397
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• 2009

c-Si wafer에 HWCVD로 증착된 a-Si:H 박막은 초기에 낮은 passivation 특성을 가지나 열처리 공정을 통해 효과적인 passivation을 가진다. 열처리 공정은 온도와 시간에 따라 큰 차이를 보인다. 이에 열선CVD를 이용하여 n type의 c-Si 기판에 a-Si:H을 증착하여 열처리 온도에 따른 Minority carrier Lifetime를 QSSPC를 통해 passivation 특성을 측정하였다. 온도는 $150^{\circ}C{\sim}270^{\circ}C$로 변화하여 측정하였다. 또한 열처리 시간을 10분씩 증가시켜 열처리 시간에 따른 passivation을 연구, 1ms에 이르는 Minority carrier lifetime을 얻었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.14-15
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• 2007

Proton irradiation technology was used for improvement of switching characteristics of the PT-IGBT. The proton irradiation was carried out at 5.56 MeV energy from the back side of processed wafers and at 2.39 MeV energy from the front side of the wafers. The on-state and off-state I-V characteristics and switching properties of the device were analyzed and compared with those of un-irradiated device and e-beam irradiated device which was conventional method for minority carrier lifetime reduction. The proton irradiated device by 5.56 MeV energy was superior to e-beam irradiated device for the on-state and off-state I-V characteristics, nevertheless turn-off time of proton irradiated device was superior to that of the e-beam irradiated device.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1996년도 재료학회 추계학술발표회
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• pp.107-107
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• 1996

• Journal of Radiation Protection and Research
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• 제48권3호
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• pp.124-130
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• 2023

Background: When bipolar junction transistors (BJTs) are used as switches, their switching characteristics can be deteriorated because the recombination time of the minority carriers is long during turn-off transient. When BJTs operate as low frequency switches, the power dissipation in the on-state is large. However, when BJTs operate as high frequency switches, the power dissipation during switching transients increases rapidly. Materials and Methods: When silicon (Si) BJTs are irradiated by fast neutrons, defects occur in the Si bulk, shortening the lifetime of the minority carriers. Fast neutron irradiation mainly creates displacement damage in the Si bulk rather than a total ionization dose effect. Defects caused by fast neutron irradiation shorten the lifetime of minority carriers of BJTs. Furthermore, these defects change the switching characteristics of BJTs. Results and Discussion: In this study, experimental results on the switching characteristics of a pnp Si BJT before and after fast neutron irradiation are presented. The results show that the switching characteristics are improved by fast neutron irradiation, but power dissipation in the on-state is large when the fast neutrons are irradiated excessively. Conclusion: The switching characteristics of a pnp Si BJT were improved by fast neutron irradiation.

• 반도체디스플레이기술학회지
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• 제13권4호
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• pp.21-25
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• 2014

The silicon nitride ($SiN_x$) film for surface passivation and anti-reflection coating of crystalline silicon solar cell is very important and it is generally deposited by plasma enhanced chemical vapor deposition (PECVD). PECVD can be divided into low and high frequency method. In this paper, the $SiN_x$ film deposited by low and high frequency PECVD method was studied. First, to optimize the $SiN_x$ film deposited by low frequency PECVD method, the refractive index was measured by varying the process conditions like $SiH_4$, $NH_3$, $N_2$ gas rate, and RF power. When $SiH_4$ gas rate was increased and $NH_3$ gas rate was decreased, the refractive index was increased. The refractive index was also increased with RF power decline. Second, to compare the characteristics of the low and high frequency PECVD $SiN_x$ film, the refractive index was measured by varying $NH_3/SiH_4$ gas ratio and RF power and the minority carrier lifetime of before and after high temperature treatment process was also measured. The refractive index of both low and high frequency PECVD $SiN_x$ film was decreased with increase in $NH_3/SiH_4$ gas ratio and RF power. After high temperature treatment process, the minority carrier lifetime of both low and high frequency PECVD $SiN_x$ film was increased and increased degree was similar. The minority carrier lifetime of low frequency PECVD $SiN_x$ was increased from $11.03{\mu}m$ to $28.24{\mu}m$ and that of high frequency PECVD $SiN_x$ was increased from $11.60{\mu}m$ to $27.10{\mu}m$.

• 한국진공학회지
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• 제13권1호
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• pp.14-21
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• 2004

오늘날 전력소자의 작동에 고주파를 사용하기 때문에 에너지 손실을 줄이기 위해 전력소자의 스위칭 속도를 증가시키는 것은 필수적이다. 본 연구에서는 $p^+- n^-$ 접합 다이오드의 스위칭 속도를 증가시킬 목적으로 minority carrier의 수명을 감소시킬 수 있는 전자조사를 실시하였다. 다이오드의 전기적 성질에 대한 전자조사의 효과를 나타냈다. 스위칭 속도는 효과적으로 증가하였다. 또한 증가될 것으로 예상되는 접합 누설 전류와 전자조사 후 정전압강하는 최적 조건의 에너지와 dose량으로 조사된 $p^+- n^-$접합 다이오드에서는 무시할 수 있는 정도로 나타났다. DLTS와 C-V 분석은 실리콘 기판에서 전자조사로 감소된 결함은 0.284eV와 0.483eV의 에너지 준위를 갖는 donor-like 결함인 것을 보여준다. 본 연구에서의 실험 결과를 고려해 보면, 전자조사는 $p^+- n^-$ 접합 다이오드 전력 소자의 스위칭 속도를 증가시켜 에너지 손실을 감소시킬 수 있는 가장 유용한 기술이라고 결론지을 수 있다.

• 한국전기전자재료학회논문지
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• 제19권1호
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• pp.7-12
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• 2006

Local minority carrier lifetime control by means of particle irradiation is an useful technology for Production of modern silicon Power devices. Crystal damage due to ion irradiation can be easily localized by choosing appropriate irradiation energy and minority tarrier lifetime can be reduced locally only in the damaged layer. In this work, proton irradiation technology was used for improving the switching characteristics of a un diode. The irradiation was carried out with various energy and dose condition. The device was characterized by current-voltage, capacitance-voltage, and reverse recovery time measurements. Forward voltage drop was increased to 1.1 V at forward current of 5 A, which was $120\%$ of its original device. Reverse leakage current was 64 nA at reverse voltage of 100 V, and reverse breakdown voltage was 670 V which was the same voltage as original device without irradiation. The reverse recovery time of device was reduced to about $20\%$ compared to that of original device without irradiation.

• 한국전기전자재료학회논문지
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• 제22권9호
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• pp.732-736
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• 2009

Protons are irradiated into SOl wafers under total dose of 100 krad, 500 krad, 1 Mrad and 2 Mrad to analyze the irradiation effect. The electrical properties are analyzed by pseudo MOSFET technology after proton irradiation. The wafers are annealed to stabilize generated defects in a nitrogen atmosphere at $300^{\circ}C$ for 1 hour because proton irradiation induces a lot of unstable defects in the surface silicon film. Both negative and positive turn-on voltages are shifted to negative direction after the irradiation. The more proton total dose, the more turn on voltage shifts. It means that positive oxide trap charge is generated in the buried oxide(BOX). The minority carrier lifetime which is analyzed by the drain current transient characteristics decreases with the increase of proton total dose. The proton irradiation makes crystal defects in the silicon film, and consequently, the crystal defects reduce the carrier lifetime and mobility. As these results, it can be concluded that pseudo MOSFET is a useful technology for the analysis of irradiated SOI wafer.

• 전기의세계
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• 제26권5호
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• pp.83-89
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• 1977

This paper described the minority carrier lifetime in Si epitaxial layer, and also the voltage (V) versus current (I) characteristics of high resistivity Si epitaxial layer0substrate junction. The measured lifetime in Si epi-layer was much shorter than in bulk, and the temperature dependence of lifetime was found to agree well with Shockley-Read model of recombination which applies to high resistivity n-type materials. The V-I curve showed; an ohmic region (I.var.V), a sublinear region (I.var.V$^{1}$2/), a space charge limited current region (I.var.V$^{2}$), and finally a negative resistance region. We investigated these phenomena by the theory of the relaxation semiconductor.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.405-408
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• 2004

In this work, Analytical model for voltage and current characteristics of NPT(Non-PunchThrough) IGBT(Insulated Gate Bipolar Transistor) was represented. voltage and current characteristics models were based on prediction on power loss of NPT IGBT during transient condition. For Analytical current model, excess carrier concentration and accumulated charge in active base width was analyzed with time variance. Analytical models were simulated by varying lifetime of excess minority carrier.