Electrothermal Reliability of the High Electron Mobility Transistor (HEMT)

Round 1

Reviewer 1 Report

The manuscript “Electrothermal reliability of the high electron mobility transistor (HEMT)” by Amar et al. study the power dissipation and the reference temperature on the operating temperature of the HEMT, and use the FORM, SORM methods to estimate the reliability. The study is mainly conducted using Comsol Multiphysics and Matlab. The results are interesting, but in my opinion, before recommending for publication, the manuscript must go through major revisions, following the guidelines reported in the following.

 

• The major concern on the science of the work is the ignorance of the thermal resistance of interface, which is very important for thermal dissipation. I suggest the author add the effect of the interface to their model.

 

• In Figure 1, “Ohmic” is spelled incorrectly.

 

• The word abbreviations of “SORM” “MPFP” don't have full names when they first appear.

 

• References seem not cited in the order in which they appear in the manuscript.

Author Response

Thank you for all your very pertinent comments. We have made all the requested changes.

Here are our responses.

The major concern on the science of the work is the ignorance of the thermal resistance of interface, which is very important for thermal dissipation. I suggest the author add the effect of the interface to their model.

 In the modeling process, we didn’t ignore the thermal resistance of the interface. However, the objective of our paper is to focus on the HEMT operating conditions (dissipated power, Reference temperature) in order to estimate the influence of these conditions on the HEMT reliability. Your remark will be the subject of another publication, in which we will study the influence of the several material layers on the component reliability.

In Figure 1, “Ohmic” is spelled incorrectly.

 We have changed the figure.  

The word abbreviations of “SORM” “MPFP” don’t have full names when they first appear.

 We have added the full names to the paper.

References seem not cited in the order in which they appear in the manuscript

We have corrected the order of the references. However, there are some references used in more sections of the paper.

Reviewer 2 Report

The conclusion should include a deeper analysis of the findings.

Author Response

Thank you for all your very pertinent comments. We have made all the requested changes.

 

The conclusion should include a deeper analysis of the findings.

We have changed the conclusion referring to your comments.

Reviewer 3 Report

The recommedation are enclosed here.

Comments for author File: Comments.pdf

Author Response

Thank you for all your very pertinent comments. We have made all the requested changes.

 

1)Please specify the shortcuts: FORM, SORM and AFNOR. In the abstract this sentence To carry out a reliable study, several methods can be used, among these methods we find SORM and FORM. should be replaced by In our study these analytical methods, like as First and Second Order Reliability Methods (FORM and SORM, respectively), were used to analyze the thermal properties. the meaning of shortcuts SORM and FORM. In the page 7, what is the meaning of the shortcut AFNOR?

We have added the full names of all these abbreviations, and we have reformulated all the sentences in your comments.

 

2)Some sentences start with small character. Please use one type of character in the

equations, like as T(X) or T(x), H(U) or H(u), Please correct the text.

We have corrected T(X). However, “u” is the realization of “U” than they are different.

 

3.) Please correct the sentences:

a, b, c, d, e, f, g, h and i

all these sentences are corrected in the new version.

 

4.) Figure 1, please add next to the small frame the label of used materials.

In figure 1 we have detailed all the used materials and their properties in table 1.

 

5.) The reference temperature in the text was 25 C, but in the figure 3 the authors describe Tref 50 C. Which temperature was used as a reference? One is operating reference and the other is substrate reference temperature?

The reference temperature used was 25°C, we have corrected it the paper.

Round 2

Reviewer 1 Report

Thank you very much for the response. As is mentioned, the major concern was about the interface thermal resistance. I am wondering if you could be more specific about how the thermal resistance was included to the model, because:

 

1. I could not find the parameters of the interfacial thermal resistance (or conductivity) used in the model.
2. It seems to me that temperature is continuous at the interface, while if the interface has thermal resistance, I expect the temperature to be saltatorial.

Author Response

Thank you for this specific remark, it's very important.

Here are our responses: 

Thank you very much for the response. As is mentioned, the major concern was about the interface thermal resistance. I am wondering if you could be more specific about how the thermal resistance was included to the model.

In our paper, the thermal boundary resistance (TBR) is represented by the nucleation layer, it's between the SiC and GaN layers ( see figure 1), and we have added its material properties in table 1. In addition, we have described it in the device description section.