MEMS device and method of forming the same
View Patent ↗A MEMS device and a forming method thereof are provided. The MEMS device includes a semiconductor substrate with a well region formed therein. A source region, a drain region and a channel region are formed in the well region. The source region and the drain region are covered by an isolating layer, and the channel region is covered by a gate dielectric layer. The device further includes a gate electrode layer which is disposed above the gate dielectric layer, with a gap disposed therebetween. The width of the gap corresponds to the width of the channel region. The MEMS can work well at high voltages with less leakage current.
1. A method for forming a MEMS device, comprising:
providing a substrate with a well region formed therein, wherein a source region, a drain region and a channel region are formed in the well region;
forming an isolating layer on the substrate;
forming an opening in the isolating layer to expose the channel region and portions of the source region and the drain region neighboring the channel region;
forming a gate dielectric layer on a bottom surface of the opening;
forming a filling layer to fill up the opening, wherein a top surface of the filling layer levels with a top surface of the isolating layer;
forming a gate electrode layer on the filling layer and the isolating layer; and
removing the filling layer to form a gap between the gate electrode layer and the gate dielectric layer.
2. The method for forming a MEMS device according to claim 1 , wherein the step for forming the gate electrode comprises: forming a gate electrode film on the filling layer and the isolating layer; forming a patterned photoresist layer corresponding to the gate electrode layer on the gate electrode film; and etching the gate electrode film using the patterned photoresist layer as a mask to form the gate electrode layer.
3. The method for forming a MEMS device according to claim 1 , wherein the gate electrode layer exposes portions of the filling layer.
4. The method for forming a MEMS device according to claim 1 , wherein the gate electrode layer has a single-layer structure or a multi-layer stack structure.
5. The method for forming a MEMS device according to claim 4 , wherein the single-layer structure comprises conducting material.
6. The method for forming a MEMS device according to claim 4 , wherein the gate electrode layer has a three-layer stack structure comprising a metal layer, a silicon oxide layer formed on the metal layer and a silicon nitride layer formed on the silicon oxide layer.
7. The method for forming a MEMS device according to claim 1 , wherein the gate electrode layer comprises a width corresponding to a width of the channel region.
8. The method for forming a MEMS device according to claim 1 , wherein the filling layer comprises a material with relatively high etching selectivity with the gate electrode layer and the gate dielectric layer.