Development of the Device for Producing a Large Area Thin Film by a New Maicrowave Mode

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The objective is to produce a high density ECR plasma with the diameter larger than 20 cm using a new type of microwave mode (2.45GHz) and to prepare a large area amorphous silicon film by plasma CVD.We have performed the experiments using a multi-slot antenna develomed at Kyushu University. Obtained main results are as follows :(1) In order to study the role of microwave propagation in plasma uniformity, we measured the axial propagation of the microwave in ECR plasma using a mixer. It was found that (i) when the plasma density is low, both the R-wave and L-wave exist before the resonant point and onlythe L-wave does after the resonant point, and (ii) when the plasma density is high, only the R-wave exists.(2) The standing patterns which have been observed in the most of the experiments were formed by the L-wave.(3) We measured radially propagating waves and the propagation direction using a mixer and a phase shifter. It was found that there is the X-wave propagating across the magnetic field. The x-wave has not been observed in ECR plasma, so far.(4) We measured the parameters of the silane plasmas diluted in He or H2 with the Langmuir probe with a heater and a microwave interferometer. It was found that there are a lot of negative ions. It will be neccesary to identify negative ion species.(5) We deposited amorphous silicon films on the glass substrates and estimated the deposition rate and the conductivity. The high quality films with the deposition rate of 15 /sec were obtained.(6) We examined the dependence of the plasma parameters on the gas flow rate. It was found that higher deposition rate would be achieved above 50sccm.(7) Above results are very important data for depositing a large area thin film and the present experiments will make the advancement the study on the preparation of a large area thin film.