PECVD growth of Six:Ge1−x films for high speed devices and MEMS

Thin films of Silicon–Germanium (SiGe) were deposited by plasma enhanced chemical vapor deposition (PECVD) for use in high speed devices, Micro-electrical mechanical systems (MEMS) and bolometric infrared detectors. SiGe films grown by PECVD typically have lower stress, lower deposition temperatures and higher growth rates (200 Å/min) compared with other deposition techniques. The samples were deposited at temperatures from 500 °C to 580 °C and doped using either diborane (B2H6) or phosphine (PH3). As-deposited films had predominantly (1 1 1) and (2 2 0) texture determined by X-ray diffraction (XRD). Annealing produced crystalline material with no evidence of cracking as determined by resistivity measurements. It also produced variations of crystallite orientations with predominantly (1 1 1) texture. As-grown films exhibited compressive stresses as low as 18 MPa. Stress in annealed samples increased with increasing annealing temperature and time.