Dielectric Property Measurement of Polycrystalline Silicon at High Temperatures

The cavity technique based on frequency tuning was used to measure dielectric properties (dielectric constant, lossfactor and loss tangent) of high purity polycrystalline particulate silicon obtained from two different sources. The dielectric properties were measured as afunction of temperature (23°C to 650°C) and particle size (30 -200 mesh range). The measurements were taken at frequencies between 995MHz to 977 MHz. The dielectric constant increased sharply between 150°C to 350°C. No significant change was observed above 350°C for all samples. The loss factor initially increased with temperature reaching a maximum at about 240°C and 280°C for the two sample sources and then decreased at higher temperatures for all samples. Larger particle size samples went through a minimum in the 460°C to 470°C range. The loss tangent followed a similar trend as the loss factor but the maximums were observed at 250°C and200°C , respectively.