How do I create a semi-logarithmic chart in Microsoft Excel (Using the
chart to graph growth for sales, earnings, etc. for public companies. 
Need semi-logarithmic chart so I can fairly compare above mentioned
metrics across multiple companies with the same scale on charts.)?

Hello and thank you for your question.

Try these two methods for practice and let me know if they work for you.

Method 1:
Type a column of the following numbers, one below the other (say in
boxes A1, B1, C1 and D1):
10
100
1000
10000

Now select the column with the mouse and click on the chart 'wizard' button
http://www.fairfax.bham.sch.uk/geograph/ks3frame/Image85.gif

You'll see a box with two tabs, 'standard types' and 'custom types'
Select 'custom types' and click on 'Logarithmic'

That should do it!

Method 2:
If you already have a non-logarithmic graph, click on its y-axis and
choose Selected Axis/Scale from the format menu.
http://wwwfp.vuse.vanderbilt.edu:8888/es130/lectures/lecture6/plot_t7.gif
Click on the 'logarithmic scale' button as shown and you should have
what you want.  See
http://wwwfp.vuse.vanderbilt.edu:8888/es130/lectures/lecture6/plot_types.html

Search terms used:
"chart wizard" excel semi-log

Thanks again for letting us help!

Sincerely,
Google Answers Researcher
Richard-ga

Use an x-y scatter plot, and format the y axis to be logarithmic.