TY - JOUR
T1 - A study on the competition between bias-induced charge trapping and light-induced instability in In-Ga-Zn-O thin-film transistors
AU - Park, Jozeph
AU - Trung, Nguyen Dinh
AU - Kim, Yang Soo
AU - Kim, Jong Heon
AU - Park, Kyung
AU - Kim, Hyun Suk
N1 - Publisher Copyright:
© 2016, Springer Science+Business Media New York.
PY - 2016/6/1
Y1 - 2016/6/1
N2 - Thin-film transistors (TFTs) were fabricated using In-Ga-Zn-O (IGZO) semiconductor layers deposited under different oxygen partial pressures. The devices were subjected to negative bias stress (NBS), negative bias illumination stress (NBIS), positive bias stress (PBS) and positive bias illumination stress (PBIS). While device degradation is negligible under NBS, negative shifts in the threshold voltage (Vth) are observed in the presence of light (NBIS), of which the magnitude (ΔVth) decreases with increasing oxygen partial pressure during IGZO growth. Under PBS, the devices undergo positive Vth shifts, which become more severe with increasing oxygen content in IGZO. However, negative ΔVth values are observed under PBIS, of which the magnitude decreases with increasing oxygen content in the semiconductor. When positive gate bias is applied, the trapping of negative charge by interstitial oxygen atoms in IGZO is presumed to be the driving force inducing positive Vth shifts. On the other hand, when light is present, the generation of photo-induced excess carriers from oxygen-deficient defect sites is anticipated to be the driving force inducing negative Vth shifts. A balance between the competing mechanisms inducing either positive or negative Vth shifts must therefore be established when the devices are subjected to PBIS, for example in operating active matrix organic light emitting diode (AMOLED) displays using transparent panel arrays.
AB - Thin-film transistors (TFTs) were fabricated using In-Ga-Zn-O (IGZO) semiconductor layers deposited under different oxygen partial pressures. The devices were subjected to negative bias stress (NBS), negative bias illumination stress (NBIS), positive bias stress (PBS) and positive bias illumination stress (PBIS). While device degradation is negligible under NBS, negative shifts in the threshold voltage (Vth) are observed in the presence of light (NBIS), of which the magnitude (ΔVth) decreases with increasing oxygen partial pressure during IGZO growth. Under PBS, the devices undergo positive Vth shifts, which become more severe with increasing oxygen content in IGZO. However, negative ΔVth values are observed under PBIS, of which the magnitude decreases with increasing oxygen content in the semiconductor. When positive gate bias is applied, the trapping of negative charge by interstitial oxygen atoms in IGZO is presumed to be the driving force inducing positive Vth shifts. On the other hand, when light is present, the generation of photo-induced excess carriers from oxygen-deficient defect sites is anticipated to be the driving force inducing negative Vth shifts. A balance between the competing mechanisms inducing either positive or negative Vth shifts must therefore be established when the devices are subjected to PBIS, for example in operating active matrix organic light emitting diode (AMOLED) displays using transparent panel arrays.
KW - In-Ga-Zn-O (IGZO)
KW - Negative bias illumination stress (NBIS)
KW - Negative bias stress (NBS)
KW - Positive bias illumination stress (PBIS)
KW - Positive bias stress (PBS)
KW - Transparent thin film transistor
UR - http://www.scopus.com/inward/record.url?scp=84964039197&partnerID=8YFLogxK
U2 - 10.1007/s10832-016-0032-3
DO - 10.1007/s10832-016-0032-3
M3 - Article
AN - SCOPUS:84964039197
SN - 1385-3449
VL - 36
SP - 135
EP - 140
JO - Journal of Electroceramics
JF - Journal of Electroceramics
IS - 1-4
ER -