Influence of phosphorus doping on hydrogen content and optical losses in PECVD silicon oxynitride

PECVD Phosphorus-doped silicon oxynitride layers (n=1.5) were depositedfrom N20, 2%SiHdN2, NH3 and 5%PH3/Ar gaseous mixtures. Chemical bonds were determined by Fourier transform infrared spectrosco y N H bond concentration of the layers decreased from 3.29 X I @' to 0.45 x l & r ~ m ' 3 ~ a s the 5%PH3/Rr jlow rate increased from 0 to 60 sccm. A simultaneous decrease of 0 H related bonds was also observed within the same phosphine jlow range. The optical loss of slab-type waveguides at A=1505 nm was found to decrease from 14.1 to 6.2 dB/cm as the 5%PH3/Ar jlow rate increased from 0 to 30 sccm, respectively. Moreover, the optical loss values around A= 1400 and 1550 nm were found to decrease from 4.7 to below 0.2 dB/cm andfrom 1.8 to I. 0 dB/cm respectively. These preliminary results are very promising for applications in low-loss integrated optical devices.