Microelectromechanical system and process of making it

A microelectromechanical system comprising:

• an electrically conductive lower membrane;
• the lower membrane comprises a plurality of troughs and crests arranged alternately;
• an electrically conductive upper membrane;
• the upper membrane comprising a plurality of troughs and crests arranged alternately;
• the trough of the lower membrane are aligned with the crests of the upper membrane respectively while the crests of the lower membrane are aligned with the trough of the upper membrane respectively;
• and
• a spacer layer disposed between the lower membrane and the upper membrane, the spacer layer comprising counter electrode walls and support walls, the counter electrode walls being provided with conductive elements;
• wherein a chamber is formed between aligned one trough of the lower membrane and one crest of the upper membrane;
• chambers are respectively formed between aligned troughs of the lower membrane and crests of the upper membrane;
• the counter electrode walls are suspended in the chambers respectively;
• and
• the support walls are respectively sandwiched between the crests of the lower membrane and the troughs of the upper membrane;
• and a space is formed between aligned one crest of the lower membrane and one trough of the upper membrane and located between two adjacent support walls, and spaces are respectively formed between the crests of the lower membrane and the troughs of the upper membrane.