A study of potentiostatic and galvanostatic electrochemical etching of silicon in tetramethylammonium hydroxide (TMAH) has been carried out. In TMAH baths,, we find that biased (100) silicon etch rates increase 21% over OCP etch rates. For TMAH baths seasoned with silicon, biased silicon etch rates increase to 63% over those at OCP. Electrochemical etching eliminates the growth of hillocks on etching surfaces regardless of etchant pH, [TMAH] or silicon loading, resulting in highly smooth etching surfaces. Potentiostatic and galvanic etching yield similar etch rates and surface consistency. / Graduation date: 2003