| 摘要 |
PURPOSE:To prepare a shallow impurity region easily in a short time by a method wherein a voltage whose polarity is varied is impressed to generate plasma between a stage with a substrate disposed thereon and an opposite electrode. CONSTITUTION:An N-type single crystal substrate 5 of Si as a negative pole is set on a stage 2, and an opposite electrode 3 made of a P-type single crystal is disposed above the substrate. The stage 2 is heated up to 200-400 deg.C by a heater 4. A diluted gas of B2H6 having H2 as a base is sealed in a plasma generating apparatus 1, and a directcurrent voltage of 400-600 V is impressed between the stage 2 and the opposite electrode 3, so as to produce plasma discharge. Thereafter a polarity converter 7 is operated at every prescribed time to vary the polarity of the impressed voltage. By this method, a shallow P-type impurity region can be prepared easily in a short time.
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