MOEMS apparatus and a method for manufacturing same
A MOEMS apparatus for scanning an optical beam is formed from a double active layer silicon on insulator (DSOI) substrate that includes two active layers separated by an insulating layer. The apparatus includes an electro-static comb drive having a stator formed in a first of the two active layers and a rotor formed in a second of the two active layers. The electro-static comb drive is operative to impart a tilting motion to a micro-mirror formed in the second active layer. The MOEMS apparatus is designed such that: a) at least one of the distances created between a tooth belonging to the rotor and an adjacent tooth belonging to the stator is less than 7 μm; and the aspect ratio of the apparatus is higher than 1:20.
1. A MOEMS apparatus manufactured from a double active layer silicon on insulator (DSOI) substrate that includes two active layers separated by an insulating layer, the apparatus comprising:
an electro-static comb drive that includes a stator formed in said first of the two active layers and a rotor formed in said second of the two active layers,
wherein:
at least one distance created between a tooth belonging to said rotor and an adjacent tooth belonging to said stator is smaller than 6 μm; and
aspect ratio of said apparatus is higher than 1:20.
2. A MOEMS apparatus according to claim 1 , wherein said electro-static comb drive is selected from the group consisting of a vertical comb drive, or an in-plane comb drive.
3. A MOEMS apparatus according to claim 1 , wherein each of said rotor and stator are etched in with accuracy of ±0.5 μm.
4. A MOEMS apparatus according to claim 1 , wherein said electro-static comb drive is operative under a pull-in voltage higher than 300V.
5. A method for manufacturing a MOEMS apparatus from a double active layer silicon on insulator (DSOI) substrate that includes two active layers separated by an insulating layer, comprising:
a. etching in said first active layer a first plurality of designated shapes and at least one cavity adapted to be used as a marker;
b. etching in said second active layer at least one cavity at a location that essentially corresponds to a location of said at least one marker cavity that has been etched in said first active layer;
c. identifying through said at least one cavity etched in said second active layer, said at least one marker cavity etched in said first active layer;
d. based upon the identification made in step c, determining at least one reference point at said second active layer; and
e. in said second active layer, etching a second plurality of designated shapes each located at a pre-determined distance from said at least one reference point.
6. A method according to claim 5 , wherein etching said first plurality of designated shapes and said at least one marker cavity in said first active layer are carried out simultaneously.
7. A method according to claim 5 , wherein a thickness of said oxide layer separating said first and second active layers enables light passing through said at least one marker cavity etched in said first active layer to reach the cavity etched in said second active layer.
8. A method according to claim 5 , further comprising enlarging said at least one cavity etched in said second active layer, in case that one or more of said at least one marker cavity etched in said first active layer have not been properly identified.
9. A method according to claim 5 , further comprising converting said two layer device obtained by etching said first layer and said second layer into a one layered device.
10. A method according to claim 5 , wherein said at least one marker cavity is included in said first plurality of designated shapes.
11. A method according to claim 5 , further comprising collapsing the two layers device obtained by etching said first layer and said second layer into a one layered device.