Effects of Nitrogen and Hydrogen Codoping on the Electrical Performance and Reliability of InGaZnO Thin-Film Transistors

Abstract

Despite intensive research on improvement in electrical performances of ZnO-based thin-film transistors (TFTs), the instability issues have limited their applications for complementary electronics. Herein, we have investigated the effect of nitrogen and hydrogen (N/H) codoping on the electrical performance and reliability of amorphous InGaZnO (α-IGZO) TFTs. The performance and bias stress stability of α-IGZO device were simultaneously improved by N/H plasma treatment with a high field-effect mobility of 45.3 cm/(V s) and small shifts of threshold voltage (V). On the basis of X-ray photoelectron spectroscopy analysis, the improved electrical performances of α-IGZO TFT should be attributed to the appropriate amount of N/H codoping, which could not only control the V and carrier concentration efficiently, but also passivate the defects such as oxygen vacancy due to the formation of stable Zn-N and N-H bonds. Meanwhile, low-frequency noise analysis indicates that the average trap density near the α-IGZO/SiO interface is reduced by the nitrogen and hydrogen plasma treatment. This method could provide a step toward the development of α-IGZO TFTs for potential applications in next-generation high-definition optoelectronic displays.

Defect Self‐Compensation for High‐Mobility Bilayer InGaZnO/In2O3 Thin‐Film Transistor

“…The values of exponents α and β are dependent on the device and its operation mode, and are ideally close to 2 and 1, respectively. The normalized drain‐current noise spectral density ( S ID /) at RT fits well to the 1/ f β noise theory ( f ranges from 1 to 1000 Hz), with the representative curves shown in Figure a at V GS − V TH = 3 V and V DS = 1 V. The normalized in the bilayer IGZO/In 2 O 3 TFT is obviously decreased compared to the two single‐layer TFTs, which indicates the decreased average trap density in the bilayer stack . A slope factor of −2 observed in the normalized S ID / at f = 20 Hz and V DS = 1 V (Figure b) validates the dominance of the carrier number fluctuation theory in the LFN, which is caused by the electron trapping and detrapping at the SiO 2 /IGZO interface.…”

“…The normalized drain‐current noise spectral density ( S ID /) at RT fits well to the 1/ f β noise theory ( f ranges from 1 to 1000 Hz), with the representative curves shown in Figure a at V GS − V TH = 3 V and V DS = 1 V. The normalized in the bilayer IGZO/In 2 O 3 TFT is obviously decreased compared to the two single‐layer TFTs, which indicates the decreased average trap density in the bilayer stack . A slope factor of −2 observed in the normalized S ID / at f = 20 Hz and V DS = 1 V (Figure b) validates the dominance of the carrier number fluctuation theory in the LFN, which is caused by the electron trapping and detrapping at the SiO 2 /IGZO interface. The average interfacial trap density ( N t ) within the gate oxide can be extracted bywhere γ is the attenuation coefficient of the electron wave function within the SiO 2 dielectric and has a value of 10 8 cm −1 for the Si/SiO 2 system .…”

“…Electrical performance parameters are extracted and listed in Table 1 . It is worth noting that, generally, μ FE is largely affected by the subgap defects, while SS is mainly determined by the deep‐level traps existing in the AOS channel layer . Output curves (i.e., drain–source current versus drain voltage, I DS – V DS ) of the single‐layer IGZO and In 2 O 3 , and the bilayer IGZO/In 2 O 3 TFTs are correspondingly depicted in Figure d–f, with gate voltage V GS ranging from −2 to 14 V. The output current plateau reached in the bilayer TFT with the highest value of 3.4 µA µm −1 , in a distinct contrast to the current collapse phenomena observed in the single‐layer IGZO TFT (Figure d).…”

Influence of N2/O2 Partial Pressure Ratio during Channel Layer Deposition on the Temperature and Light Stability of a-InGaZnO TFTs

“…In previous reports, the nitrogen has been used to passivate O V -related defects within a-IGZO by forming N-metal (In, Ga and Zn) bonds [8,9]. For example, the ambient stability of N-doped a-IGZO TFTs can be enhanced by the mitigation of the oxygen absorption/desorption behavior due to the substitution of the O atom by an N atom within the a-IGZO [10].…”

Study on the sintering behavior and characterization of the IGZO ceramics by slip casting

“…Amorphous indium gallium zinc oxide (a-IGZO) applied as a transparent semiconductor has shown an outstanding electrical property in thin-film transistors. [1][2][3][4] IGZO has attracted a lot of attention in the large-area flat panel display (FPD) industry because it can overcome the difficulties which happened in the thin-film transistor produced by a-Si:H and poly-Si TFT technologies. 5 The major phases of IGZO ceramics by the mixed powder (In:Ga:Zn = 1:1:1) was an InGaZnO 4 phase which owns the crystal structure of rhombohedral (R 3m).…”