You can take your carboy, and put it in a refrigerator...or cool it down to under 40F some other way. This will cause the yeast to go dormant and stop producing alcohols. While this works, there are several bad things about it:
1. When you bottle, and warm the beer back up you risk having bottle bombs due to all the extra sugars still in the beer.
2. After alcohol production, there are many chemicals and other byproducts left from the yeast activity. After the yeast has consumed the sugars, it will "clean up" after itself and you will be left with a cleaner tasting beer. If you prevent the yeast from doing this, you run the risk of off-flavors.
3. Depending on the style, you may be left with an overly-sweet beer. You haven't let the yeast consume all possible sugars in the beer so your beer may not be true to the style you're brewing.