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Institute of Korean Electrical and Electronics Engineers (한국전기전자학회)
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Thermal treatments effects on the properties of zinc tin oxide transparent thin film transistors

Zinc tin oxide 투명박막트랜지스터의 특성에 미치는 열처리 효과

  • Ma, Tae Young (Dept. of Electrical Engineering & ERI, Gyeongsang National University)
  • Received : 2019.04.10
  • Accepted : 2019.06.04
  • Published : 2019.06.30
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Abstract

$ZnO-SnO_2(ZTO)$ was deposited by RF magnetron sputtering using a ceramic target whose Zn atomic ratio to Sn is 2:1 as a target, and the crystal structure variation with thermal treats was investigated. Transparent thin film transistors (TTFT) were fabricated using the ZTO films as active layers. About 100 nm-thick $Si_3N_4$ film grown on 100 nm-thick $SiO_2$ film was adopted as gate dielectrics. The mobility, threshold voltage, $I_{on}/I_{off}$, and interface trap density were obtained from the transfer characteristics of ZTO TTFTs. The effects of substrate temperature, and post-annealing on the property variation of ZTO TTFT were analyzed.

Zn와 Sn의 원자비가 2:1인 타겟을 고주파 스파터링하여 $ZnO-SnO_2(ZTO)$박막을 증착하고 열처리에 따른 구조적 특성변화를 조사하였다. 이 ZTO박막을 활성층으로 사용하여 투명박막트랜지스터(TTFT)를 제조하였다. 약 100 nm 두께의 $SiO_2$위에 100 nm의 $Si_3N_4$막을 기른 후 TTFT의 게이트 절연막으로 채택하였다. TTFT의 전달 특성을 통해 이동도, 문턱전압, 작동전류-차단전류 비($I_{on}/I_{off}$), 계면트랩밀도를 구하였다. 기판 가열 및 후속 열처리가 ZTO TTFT의 특성 변화에 미치는 영향을 분석하였다.

Keywords

JGGJB@_2019_v23n2_375_f0001.png 이미지

Fig. 1. Schematic diagram of ZTO TTFT. 그림 1. ZTO TTFT의 단면도

JGGJB@_2019_v23n2_375_f0002.png 이미지

Fig. 2. Raman spectra of ZTO target and film. 그림 2. ZTO 타겟 및 박막의 Raman 스펙트라

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Fig. 3. XRD patterns of ZTO films. 그림 3. ZTO박막의 XRD 패턴

JGGJB@_2019_v23n2_375_f0004.png 이미지

Fig. 4. ID–VDS characteristics of TTFT(0, 400). 그림 4. TTFT(0, 400)의 ID–VDS 특성

JGGJB@_2019_v23n2_375_f0005.png 이미지

Fig. 5. (a) IDvs VGS, and (b) $\sqrt[]{I_D}$ vs VGS. 그림 5. (a) ID 대 VGS 및 (b) $\sqrt[]{I_D}$ 대 VGS

Table 1. Summary of the properties of ZTO TTFTs. 표 1. ZTO TTFT의 특성 요약

JGGJB@_2019_v23n2_375_t0001.png 이미지

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