| 摘要 |
PURPOSE:To widen the range of flow rate of raw gas in which film thickness is made uniform, and the film thickness of a vapor growth layer is easily made uniform not only on the wafer surface but also on the region between the wafers by a method wherein the main jetting direction of raw gas is prevented rom becoming coincident with the direction in which a gas feeding nozzle and a wafer rotation center are linked. CONSTITUTION:In the diagram showing a wafer 11 and a gas feeding nozzle 16, 19 shows the raw gas came out from a jetting-out hole, and x' shows the main jetting-out direction of raw gas. O indicates the center of rotation of the wafer 11. The direction linking the nozzle 16 and the rotational center O is shown by (x). (l) indicates the length of a vertical line brought down to x'-axis from the center of rotation of the wafer. The distribution of concentration of raw gas in the direction vertical to the x'-axis from the point P can be brought to approximate to g.e<-p2/delta2> using the distance P in y'-axis direction measured from the point P. However, (g) is the concentration of raw gas at the point P, and delta shows the direction in which the concentration of raw gas becomes 1/e. By using the approximate expression as above-mentioned, the relation of the jetting direction and the x-axis is formed in such a manner that the distance (l) becomes about 40%-80% of the attenuation distance delta.
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