The 70th JSAP Spring Meeting 2023

Presentation information

Oral presentation

21 Joint Session K "Wide bandgap oxide semiconductor materials and devices" » 21.1 Joint Session K "Wide bandgap oxide semiconductor materials and devices"

[15p-E102-1~17] 21.1 Joint Session K "Wide bandgap oxide semiconductor materials and devices"

Wed. Mar 15, 2023 1:30 PM - 6:15 PM E102 (Building No. 12)

Mamoru Furuta(Kochi Univ. of Tech.), Keisuke Ide(Tokyo Tech), Ken Goto(Tokyo Univ. Agri. and Tech.)

1:45 PM - 2:00 PM

[15p-E102-2] [The 7th Thin Film and Surface Physics Division Young Researcher Award Speech] Heterogeneous metal oxide channel structure for ultra-high sensitivity phototransistor with modulated operating conditions

KuanJu Zhou1, Keisuke Ide2, Takayoshi Katase2, Toshio Kamiya2,3, TingChang Chang1 (1.National Sun Yat-Sen Univ, 2.MSL Tokyo Tech, 3.MDX Tokyo Tech)

Keywords:InGaZnO TFTs, Heterogeneous channel structure, Ultraviolet light sensing

With the demand for high mobility materials, a heterogeneous channel structure and Sn-doped IGZO was introduced into oxide semiconductors to improve the electrical properties. In addition, the Sn-doped IGZO TFTs can effectively reduce localized states and deep-level traps in IGZO [1]. Moreover, buried channel designs are implemented using higher zinc content IGZO in the top and bottom channel layers to improve the overall electrical performance [2]. In this work, these designs for TFTs leads to high mobility and lower subthreshold swing (S.S.) properties.
Many studies have been conducted on the use of amorphous oxides as optical sensors, but achieving both sensing characteristics and device operation stability remains a challenge [3]. We propose a heterogeneous channel structure and then realize a phototransistor that operates stably even after 200 repeated measurements while improving the photoresponse on/off ratio by 4 orders of magnitude. Furthermore, we study the operating parameters such as voltage pulse width and voltage value in detail, demonstrate optimized operating conditions, and carefully discuss the operating mechanism and negative bias illumination stress (NBIS) degradation [4]. By improving the operation pulse modulation, the ultraviolet sensing ability is effectively improved, and the sensing on/off ratio of 4 orders of magnitude is still maintained after working for 10000 s. A high-sensitivity, ultra-high-endurance phototransistor has been developed, and the results show that it can effectively improve the reliability of ultraviolet sensing.