• Transactions on Electrical and Electronic Materials
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• 제7권1호
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• pp.1-6
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• 2006

Hot carrier degradation and roll off characteristics of threshold voltage ($V_{t1}$) on NMOSFETs as I/O transistor are studied as a function of Lightly Doped Drain (LDD) structures. Pocket dose and the combination of Phosphorus (P) and Arsenic (As) dose are applied to control $V_{t1}$ roll off down to the $10\%$ gate length margin. It was seen that the relationship between $V_{t1}$ roll off characteristic and substrate current depends on P dopant dose. For the first time, we found that the n-p-n transistor triggering voltage ($V_{t1}$) depends on drain current, and both $I_{t2}$ and snapback holding voltage ($V_{sp}$) depend on the substrate current by characterization with a transmission line pulse generator. Also it was found that the improved lifetime for hot carrier stress could be obtained by controlling the P dose as loosing the $V_{t1}$ roll off margin. This study suggests that the trade-off characteristic between gate length margin and channel hot carrier (CHC) lifetime in NMOSFETs should be determined by considering Electrostatic Discharge (ESD) characteristic.

• 대한전자공학회논문지SD
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• 제49권1호
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• pp.8-14
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• 2012

전체 채널 폭은 같지만 핀 수와 핀 폭이 다른 n-채널 MuGFET의 특성을 측정 비교 분석하였다. 사용된 소자는 Pi-gate 구조의 MuGFET이며 핀 수가 16이며 핀 폭이 55nm인 소자와 핀 수가 14이며 핀 폭이 80nm인 2 종류의 소자이다. 측정 소자성능은 문턱전압, 이동도, 문턱전압 roll-off, DIBL, inverse subthreshold slope, PBTI, hot carrier 소자열화 및 드레인 항복전압 이다. 측정 결과 핀 폭이 작으며 핀 수가 많은 소자의 단채널 현상이 우수한 것을 알 수 있었다. PBTI에 의한 소자열화는 핀 수가 많은 소자가 심하며 hot carrier에 의한 소자열화는 비슷한 것을 알 수 있었다. 그리고 드레인 항복 전압은 핀 폭이 작고 핀 수가 많은 소자가 높은 것을 알 수 있었다. 단채널 현상과 소자열화 및 드레인 항복전압 특성을 고려하면 MuGFET소자 설계 시 핀 폭을 작게 핀 수를 많게 하는 것이 바람직하다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.749-752
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• 2014

Spacer 유무와 핀 폭, 채널길이에 따른 n채널 MuGFET의 단채널 및 열화 특성을 비교 분석 하였다. 사용된 소자는 핀 수가 10인 Tri-Gate이며 Spacer 유무에 따른 핀 폭이 55nm, 70nm인 4종류이다. 측정한 소자 특성은 DIBL, subthreshold swing, 문턱전압 변화 (이하 단채널 현상)과 소자열화이다. 측정 결과, 단채널 현상은 spacer가 있는 것이 감소하였고, hot carrier degradation은 spacer가 있고 핀 폭이 작은 것이 소자열화가 적었다. 따라서, spacer가 있는 LDD(Lightly Doped Drain) 구조이며 핀 폭이 작은 설계방식이 단채널 현상 및 열화특성에 더욱 바람직하다.

• 전자공학회논문지A
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• 제30A권8호
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• pp.63-71
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• 1993

To verify validity of the steady-state Nyquist theorem and the steady-state Nyquist theorem with hot carrier effects in semiconductor devices, we calculate thermal noise in n-i-n structures using both the steady-state Nyquist theorem and the Monte-Carlo method, and compare the results from these two-methods. When the carrier temperature is not far from the lattice temperature, the results from both methods agree with each other very well, but in the hot carrier regime there are some discrepancies. Our results support the argument that for MOSFETs and MESFETs operating in the linear region, the channel thermal noise should be explained by the steady-state Nyquist theorem rather than by the existing theories.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.172-175
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• 2009

n-type crystalline silicon wafers were passivated with intrinsic a-Si:H thin films on both sides using HWCVD. Minority carrier lifetime measurement was used to verify interface passivation properties between a-Si:H thin film and crystalline Si wafer. Thin film interface characteristics were investigated depending on $H_2/SiH_4$ ratio and hot wire deposition temperature. Vacuum annealing were processed after deposition a-Si:H thin films on both sides to investigate thermal effects from post process steps. We noticed the effect of interface passivation properties according to $H_2/SiH_4$ ratio and hot wire deposition temperature, and we had maximum point of minority carrier lifetime at H2/SiH4 10 ratio and $1600^{\circ}C$ wire temperature.

• 한국전기전자재료학회논문지
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• 제21권8호
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• pp.687-694
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• 2008

This paper is focused on the improvement of MOS device reliability related to deuterium process. The injection of deuterium into the gate oxide film was achieved through two kind of method, high-pressure annealing and low-energy implantation at the back-end of line, for the purpose of the passivation of dangling bonds at $SiO_2/Si$ interface. Experimental results are presented for the degradation of 3-nm-thick gate oxide ($SiO_2$) under both negative-bias temperature instability (NBTI) and hot-carrier injection (HCI) stresses using P and NMOSFETs. Annealing process was rather difficult to control the concentration of deuterium. Because when the concentration of deuterium is redundant in gate oxide excess traps are generated and degrades the performance, we found annealing process did not show the improved characteristics in device reliability, compared to conventional process. However, deuterium ion implantation at the back-end process was effective method for the fabrication of the deuterated gate oxide. Device parameter variations under the electrical stresses depend on the deuterium concentration and are improved by low-energy deuterium implantation, compared to conventional process. Our result suggests the novel method to incorporate deuterium in the MOS structure for the reliability.

• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.20-23
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• 2012

In this paper, we investigated the device performance on fluorine implantation, hot carrier reliability and RTS (random telegraph signal) noise characteristics of NMOSFETs. The capacitance of the fluorine implanted NMOSFET decreased due to the increase of the gate oxide thickness. RTS noise characteristics of the fluorine implated NMOSFET was improved approximately by 46% due to the decrease of trap density at Si/$SiO_2$ interface. The improved gate oxide quality also results in the longer hot carrier life time.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.142-142
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• 2012

최근 반도체 산업의 발전과 동시에 소자의 집적화에 따른 단채널 효과가 문제되고 있다. 채널 영역에 대한 게이트 영역의 제어능력이 떨어지면서 누설전류의 증가, 문턱전압의 변화가 발생하며, 이를 개선하기 위해 이중게이트 혹은 다중게이트 구조의 트랜지스터가 제안되었다. 하지만 채널길이가 수십나노미터 영역으로 줄어듦에 따라 소스/드레인과 채널간의 접합형성이 어렵고, 고온에서 열처리 과정을 거칠 경우 채널의 유효길이를 제어하기 힘들어진다. 최근에 제안된 Junctionless 트랜지스터의 경우, 소스/드레인과 채널간의 접합이 없기 때문에 접합형성 시 발생하는 공정상의 문제뿐만 아니라 누설전류영역을 개선하며, 기존의 CMOS 공정과 호환되는 이점이 있다. 한편, 집적화되는 반도체 기술에 따라, 동작 시 발생하는 스트레스가 소자의 신뢰성에 중요한 요인으로 작용하게 되며, 현재 Junctionless 트랜지스터의 신뢰성 특성에 관한 연구가 부족한 상황이다. 따라서, 본 연구에서는 Junctionless 트랜지스터의 NBTI 특성과 hot carrier effect에 의한 신뢰성 특성을 분석하였다. Junctionless 트랜지스터의 경우, 축적모드로 동작하기 때문에 스트레스에 의해 유기되는 캐리어의 에너지가 낮다. 그 결과, 반전모드로 동작하는 Junction type의 트랜지스터에 비해 스트레스에 의한 subthreshold swing 기울기의 열화와 문턱전압의 이동이 감소하였다. 또한 소스/드레인과 채널간의 접합이 없기 때문에 hot carrier effect에 의한 게이트 절연막 및 계면에서의 열화가 개선되었다.

• 대한전자공학회논문지
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• 제27권9호
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• pp.1409-1418
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• 1990

Characteristics of NMOS transistors with phosphorus source/drain junctions formed by two-step rapid thermal diffusion (RTD) process using a solid diffusion source have been investigated. Phosphorus profiles after RTD were measured by SIMS analysis. In the case of 1100\ulcorner, 10sec RTD of, P, the specific contact resistance of n+ Si-Al was 2.4x10**-7 \ulcorner-cm\ulcorner which is 1/5 of the As junction The comparison fo P junction devices formed by RTD and conventional As junction devices shows that both short channel effect and hot carrier effect of P junction devices are smaller than those of As junction devices when the devices have same junction depths. P junction device had maximum of 0.4 times lower Isub/Id than As junction device. Characteristics of P junction formed by several different RTD conditions have been compared and 1000\ulcorner RTD sample had the smaller hot carrier generation. Also, it has been shown that the hot carrier generation can be futher reduced by forming the P junctions by 3-step RTD which has RTO-driven-in process additionally.

• Journal of information and communication convergence engineering
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• 제11권4호
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• pp.288-292
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• 2013

In this paper, a carbon implant is investigated in detail from the perspectives of performance advantages and side effects for the thick n-type metal-oxide-semiconductor field-effect transistor (n-MOSFET). Threshold voltage ($V_{th}$) adjustment using a carbon implant significantly improves the $V_{th}$ mismatch performance in a thick (3.3-V) n-MOS transistor. It has been reported that a bad mismatch occurs particularly in the case of 0.11-${\mu}m$ $V_{th}$ node technology. This paper investigates a carbon implant process as a promising candidate for the optimal $V_{th}$ roll-off curve. The carbon implant makes the $V_{th}$ roll-off curve perfectly flat, which is explained in detail. Further, the mechanism of hot carrier injection lifetime degradation by the carbon implant is investigated, and new process integration involving the addition of a nitrogen implant in the lightly doped drain process is offered as its solution. This paper presents the critical side effects, such as Isub increases and device performance shifts caused by the carbon implant and suggests an efficient method to avoid these issues.