A micro-electro-mechanical transducer (such as a cMUT) having a non-flat surface is disclosed. The non-flat surface may include a variable curve or slope in an area where a spring layer contacts a support, thus making a variable spring model as the spring layer vibrates. The non-flat surface may be that of a non-flat electrode optimized to compensate the dynamic deformation of the other electrode during operation and thus enhance the uniformity of the dynamic electrode gap during operation. Methods for fabricating the micro-electro-mechanical transducer are also disclosed. The methods may be used in both conventional membrane-based cMUTs and cMUTs having embedded springs transporting a rigid top plate.