Abstract: Methods for manufacturing micromachined devices and the devices obtained are disclosed. In one embodiment, the method comprises providing a structural layer comprising an amorphous semiconductor material, forming a shielding layer on a first portion of the structural layer and leaving exposed a second portion of the structural layer, and annealing the second portion using a first fluence. The method further comprises removing the shielding layer, and annealing the first portion and the second portion using a second fluence that is less than half the first fluence. In an embodiment, the device comprises a substrate layer, an underlying layer formed on the substrate layer, and a sacrificial layer formed on only a portion of the underlying layer. The device further comprises a structural layer that is in contact with the underlying layer and comprises a first region annealed using a first fluence and a second region annealed using a second fluence.

Abstract: A method is provided for controlling the average stress and the strain gradient in structural silicon germanium layers as used in micromachined devices. The method comprises depositing a single silicon germanium layer on a substrate and annealing a predetermined part of the deposited silicon germanium layer. The process parameters of the depositing and/or annealing steps are selected such that a predetermined average stress and a predetermined strain gradient are obtained in the predetermined part of the silicon germanium layer. Preferably a plasma assisted deposition technique is used for depositing the silicon germanium layer, and a pulsed excimer laser is used for local annealing, with a limited thermal penetration depth. Structural silicon germanium layers for surface micromachined structures can be formed at temperatures substantially below 400° C., which offers the possibility of post-processing micromachined structures on top of a substrate comprising electronic circuitry such as CMOS circuitry.