Bova (Taiwan)

A capacitively coupled VHF H2 plasma (60 MHz) was produced at high pressures, and plasma parameters were examined as a function of pressure and power at different discharge gaps (10, 15, and 20 mm). Here, a balanced power feeding method was adopted to avoid anomalous discharges. It was found that the electron density peaked at a certain pressure. As the discharge gap decreased, the peak pressure increased. The electron temperatures at the discharge gaps of 10 and 20 mm were approximately 8 and 3 eV at high pressures, respectively. In addition, we found that the sheath potential corresponding to the ion bombardment energy with the discharge gap of 10 mm was lower than the theoretical value calculated on the basis of the sheath theory, suggesting the existence of negative ions. Estimation of negative ion concentration was attempted on the basis of the sheath theory taking into consideration negative ions.

Abstract This paper studies the poly-Si crystallization mechanism under the high power (200 W) Nd:YAG solid state pulsed laser annealing system. It is found that the Gaussian-distributed laser beam profile successfully produce large super lateral growth process window. The devices in the SLG process window exhibit field-effect mobility around 250 cm2/V.s and the threshold voltage lower than 1 V. The influence of a-Si film thickness and the laser scan pitch on the process window is also carefully investigated.