Journal of the Korea Institute of Information and Communication Engineering (한국정보통신학회논문지)

The Korea Institute of Information and Commucation Engineering (한국정보통신학회)
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Electrical Characteristics of Ambipolar Thin Film Transistor Depending on Gate Insulators

게이트 절연특성에 의존하는 양방향성 박막 트랜지스터의 동작특성

  • Oh, Teresa (Department of Semiconductor Engineering, Cheongju University)
  • Received : 2014.01.28
  • Accepted : 2014.03.25
  • Published : 2014.05.31
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Abstract

To observe the tunneling phenomenon of oxide semiconductor transistor, The Indium-gallum-zinc-oxide thin film transistors deposited on SiOC as a gate insulator was prepared. The interface characteristics between a dielectric and channel were changed in according to the properties of SiOC dielectric materials. The transfer characteristics of a drain-source current ($I_{DS}$) and gate-source voltage ($V_{GS}$) showed the ambipolar or unipolar features according to the Schottky or Ohmic contacts. The ambipolar transfer characteristics was obtained at a transistor with Schottky contact in a range of ${\pm}1V$ bias voltage. However, the unipolar transfer characteristics was shown in a transistor with Ohmic contact by the electron trapping conduction. Moreover, it was improved the on/off switching in a ambipolar transistor by the tunneling phenomenon.

본 연구는 산화물반도체트랜지스터의 터널링 현상을 살펴보기 위해서 게이트 절연막으로서 SiOC 박막을 사용하고 채널층으로 IGZO를 이용하여 트랜지스터를 제작 하였다. SiOC 박막은 분극이 작아질수록 비정질특성이 우수해지면서 절연특성이 좋아진다. SiOC 게이트 절연막과 채널 층 사이의 계면에 존재하는 접합특성은 SiOC의 분극특성에 따라서 달려졌다. 드레인소스 전류($I_{DS}$)와 게이트소스 전압($V_{GS}$)의 전달특성은 분극이 낮은 SiOC를 사용할 경우 양방향성 전달특성이 나타나고 분극이 높은 SiOC 게이트 절연막을 사용할 경우 단방향성 전달 특성이 나타났다. 터널링에 의한 양방향성 트랜지스터의 경우 바이어스 인가 전압이 낮은 ${\pm}1V$의 영역에서 쇼키접합을 나타냈었지만 트래핑효과에 의한 단방향성 트랜지스터의 경우 오믹접합 특성을 나타내었다. 특히 양방향성 트랜지스터의 경우 터널링 현상에 의하여 on/off 스위칭 특성이 개선되었다.

Keywords

References

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