High-Performance Amorphous InGaSnO Thin-Film Transistor with ZrAlO_x Gate Insulator by Spray Pyrolysis

Round 1

Reviewer 1 Report

Chang et al., report the studies of amorphous gallium indium tin oxide (a-IGTO) thin-film transistors (TFTs) with ZrAlO_X gate insulator by spray pyrolysis, particularly focusing on the impact of Ga ratio on TFT electrical performance and stability. Overall, the work is very well executed, written, and presented. The work could be strengthened by addressing the minor comments below.

1. For zirconium aluminum oxide, both ZAO and ZrAlO terminologies are used. Do they indicate any difference?

2. In Fig. 4b, the mobility drops abruptly from Ga ratio of 10% to 15%, explained by “modified material structure” on line 130. Could the authors elaborate more on this?

Also please specify drain voltage for these transfer curves. 

 

3. The lines 137-139 seem redundant to lines 129-132.

4. The stress test in Fig. 4b is carried out at 10% Ga ratio. Out of curiosity, if the authors were to perform the same experiment on different Ga ratios, would you see decreasing V_TH shift with increasing Ga ratio?

Author Response

1) For zirconium aluminum oxide, both ZAO and ZrAlO terminologies are used. Do they indicate any difference?

Answer:

Thank you very much for your valuable comment.

There is no difference between the two terms (ZAO and ZrAlO). Since both ZAO and ZrAlO are abbreviated from zirconium aluminum oxide, and they were defined as ZAO in the revised manuscript.

 

 

2) In Fig. 4b, the mobility drops abruptly from Ga ratio of 10% to 15%, explained by “modified material structure” on line 130. Could the authors elaborate more on this? Also please specify drain voltage for these transfer curves.

Answer:

Thank you very much for your valuable comment.

Ga act as a good carrier suppressor, thus, the excess gallium ratio reduces the carrier concentration in IGTO. The selection of an appropriate ratio of carrier suppressor is a vital parameter to control the carrier concentration. In this work, 10% Ga in IGTO film exhibits smooth surface morphology and fever oxygen-related defects such as oxygen vacancy (Vo) and hydroxyl groups (-OH), which gives a good interface with the gate insulator. All the transfer curves of the a-IGTO TFT were measured a constant drain voltage (V_DS) of 0.1V.

 

 

3) The lines 137-139 seem redundant to lines 129-132.

Answer:

Thank you very much for your valuable comment.

We deleted the redundant lines in the revised manuscript.

 

4) The stress test in Fig. 4b is carried out at 10% Ga ratio. Out of curiosity, if the authors were to perform the same experiment on different Ga ratios, would you see decreasing VTH shift with increasing Ga ratio?

Answer:

Thank you very much for your valuable comment.

We performed positive bias temperature stress (PBTS) test on the optimized IGTO TFT, which is due to its better electrical and optical properties compared to other Ga doping ratios.

 

Author Response File: Author Response.docx

Reviewer 2 Report

High-Performance of Amorphous InGaSnO Thin Film Tran-2 sistor with ZrAlOx Gate Insulator by Spray Pyrolysis

 

After careful revision, this work is not suitable for publication in its current state I recommend addressing all these comments and then resubmitting your revised work to be re-evaluated.

The introduction part must be improved. In this part, you mention the amorphous TFTs and Metal-Oxides compounds by chemical techniques. However, the purpose of a transistor is to be used in an electronic circuit. So, add applications in which your TFT can be employed.

I recommend adding some references such as follow to enhance the introduction and show the relevance of TFTs.

IEEE Transactions on Nuclear Science ( Volume: 69, Issue: 6, June 2022), DOI: 10.1109/TNS.2022.3171695

P. G. Bahubalindruni et al., “High-Gain Transimpedance Amplifier for Flexible Radiation Dosimetry Using InGaZnO TFTs,” IEEE J. Electron Devices Soc., vol. 6, pp. 760–765, 2018, doi: 10.1109/JEDS.2018.2850219.

The fabrication details must be added. The photolithography mask must be added here and in fig 1.

Regarding to Fig 1. Why active layer is so thin 20 nm. Explain it deeply because a higher current is expected for thicker and also less surface scattering should be expected.

Fig 2 must be enhanced it does not look like a paper image. Also, it seems like it does not change the function of Ga molar fraction. Also, add a label about the corresponding peak around 25°.

Same for figure 3 d). it seems like it does not change the function of Ga molar fraction. So, it must be enhanced. Furthermore, the fermi level must be labeled.

Report the transconductance value from Id vs Vgs.

In addition, VDS=0.1 is too low, the transistor is in the linear region. So, what happened to the curve for VDS = VDsat.

Figure 5 must be before, figure 4. It is not possible to see the differences in figures 5 a,b,c, etc. So, what’s the benefit for the reader?. I Suggest reporting the XPS graph as is reported typically elsewhere: Optical Materials 111 (2021) 110541

For transport, properties calculate the correct value of Mobility.

You mentioned that (VDS ≥ VGS–VTH) was obtained by using the equation.

However, this approximation is very superficial, you must revise amorphous TFT models to extract accurate mobility. See the model for poly type TFT reported in : IEEE Transactions on Nuclear Science ( Volume: 69, Issue: 6, June 2022), DOI: 10.1109/TNS.2022.3171695

and look more accurate for amorphous TFT.

 

 

 

 

 

 

 

 

 

Author Response

Dear Reviewer,

Thank you very much for your valuable comments.

Please find the attached file for the response letter.

Thank you.

 

Kind regards,

Bukke Ravindra Naik

(Submitting author)

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I am satisfied with the answer given by the authors. So, I recommend to publish this work.

I just recommend to enhance your mobility model because for TFT there are more parameters to consider. Otherwise, mention that it is just a simple approach of the mobility.