Monitoring of the thermal annealing of HDP-Si oxides by positron annihilation and thermal desorption spectrometry (poster session)

Abstract The thermal annealing of 1.5 μm thick SiO 2 layers deposited on Si with a High Density Plasma (HDP) has been monitored by Thermal Desorption Spectrometry (TDS), Fourier Transform Infra-Red absorption (FTIR) and Positron Annihilation Doppler Broadening (PADB). Two samples were prepared with different production conditions (substrate temperature, Ar flow, ratio) in order to get oxide layers rich in SiH bonds or rich in SiOH bonds. The deposition temperatures of these layers were 545 K and 575 K, respectively. The formation of SiH rich and SiOH rich oxides was confirmed by FTIR absorption measurements. Desorption measurements showed that at a heating rate of 5 K/s release of hydrogen takes place around 1100 K. For the layer deposited at 575 K additional release of hydrogen is observed at 900 K. In both samples argon release is seen around 1200 K. The release of hydrogen at 1100 K is consistent with FTIR measurements at annealed samples. The absorption peaks associated with the SiH and SiOH bonds only disappear after heating above 1000 K. For the PADB measurements thermal anneals were carried out from 300 to 1300 K in steps of 50 and 100 K of 16 min duration. The positron measurements show different annealing behavior of the two oxides. It is observed that up to 1200 K the 545 K oxide shows a significant higher value for the defect parameter. The argon and hydrogen release is observed by an increase of the defect parameter at 1000 K.