MEM structure having reduced spring stiction

A micro-electromechanical (MEM) structure comprising:

• a proof mass movable with respect to a substrate;
• a spring anchor rigidly coupled to the substrate;
• a tether spring, the proof mass physically coupled to the spring anchor via the tether spring, wherein the tether spring includes a first portion and a second portion in a folded configuration;
• and
• a first structure rigidly coupled to the substrate, the first structure includes at least a portion located between the first portion and the second portion, the first structure including a first major surface facing a first wall of the first portion, the first structure including a second major surface facing a second wall of the second portion, the first major surface comprises a first plurality of notches, the second major surface comprises a second plurality of notches.

A micro-electromechanical (MEM) structure comprising:

• a proof mass located above a substrate and movable with respect to the substrate;
• a spring anchor located above the substrate and rigidly coupled to the substrate;
• a tether spring integrally formed with the proof mass, the proof mass physically coupled to the spring anchor via the tether spring, the tether spring comprising an elongated portion having a vertical wall;
• and
• a first structure rigidly coupled to the substrate, the first structure including a first major vertical surface facing the vertical wall of the tether spring, wherein the first major vertical surface includes a plurality of vertically oriented notches, each notch of the plurality of vertically oriented notches is laterally spaced along the vertical wall and separated by at least a first distance from an adjacent notch of the plurality of vertically oriented notches, wherein each notch of the plurality of vertically oriented notches has a lateral width that is equal to or less than the first distance, the first structure including a first extension laterally extending from the first major vertical surface towards the vertical wall.