ECE 1406 SUPREM Project #1, Due 5/13/02
This project consists of modeling the field oxidation process and the gate oxidation process used in the lab on SUPREM 4. This is a short introductory project, and the written report should be fairly short. However, the simulation you build in this project is the beginning of simulating the entire transistor process as we look toward the end of the quarter. Here, you will be simulating the initial ion implant the wafers recieved before the lab started, as well as the field and gate oxidations. You will see how the dopant diffuses into the wafer with the oxidation processes. In this project, the questions concern only the oxide thickness, even though you are simulating the diffusion of the phosphorus impurities also.
You will determine the field and gate oxide thicknesses and compare the results with measurements from the lab and analytical (homework-type) calculations (which you have probably already done for the lab). This means that you should give me 3 numbers for each of the desired quantities below.
Also note that all the times, temperatures, temperature ramp rates, energies and doses need to be entered. None of the ones in the example file necessarily correspond to YOUR wafers. You should use the doping of the wafer determined from you four point probe measurement the first week of lab for the substrate doping.
You should find, using both Suprem and analytical methods, and comparing with lab results (give 3 numbers for each quantity):
1. The initial field oxide thickness.
2. The gate oxide thickness. (A different simulation run than question 3.)
3. The field oxide thickness after the gate oxidation. (The file is initially set up this way.)
4. Doping as a function of depth, the plot from the simulation. (No comparison with lab results here.)
5. Please turn in your SUPREM input file.
The easiest way do do this project is to modify the following file with the parameters of the process you used in the lab.
Also show your analytical calculation.
There is a quick guide to running TMA SUPREM 4 on the web site. (Suprem 4 Instructions)
To get started, first try running the file s4fieldgate0304.inp as written. In the original form, it is a file that outputs graphs to the screen. This works on some workstations but maybe not on others.
You can modify the file to output to a postscript file, nfile.ps, instead of the screen, by deleting the $ in front of the first OPTION statement. ($ indicates a comment line, so as I have written the file, the OPTION statement is not active.) With the OPTION statement active, the file prints the graph to nfile.ps. You can view the nfile.ps by typing ghostview nfile.ps. This should work on any workstation, or even remotely on another computer, if you use a local postscript viewer.
1. To get the gate oxide thickness you must etch the field oxide before growing the gate oxide. You will need to remove the comment from the etch line.
2. I have entered some ramps for the first oxidation step to show you what the syntax is, but you need to enter the proper times and temperatures for all oxidation steps. Different lab sections used slightly different processes. Pay attention to the oxidation ambient, time, and temperatures.
The ramp rate is given by the parameter T.RATE and is in degrees (C) /minute.
You may want to simulate the ramp during the push as well as the ramp during the oxidation - this will probably have a relatively small effect.
For the push and pull ramps, or for some sections for the temperature ramps, if you want to use 15% oxygen in nitrogen, you would replace the WetO2 or DryO2 parameter with two parameters F.O2=.15 F.N2=.85
I put an example of a push ramp (not necessarily with the correct parameters) in the file - it starts at 800 because Suprem does not like lower temperatures, and lower temperatures do not matter to the final result.