| 摘要 |
PURPOSE:To make it possible to measure the amount of implanted ions with high precision, by implanting ions having an opposite conductivity imparting type into a semiconductor substrate, applying a masking material serving against implanted ions on the substrate, again implanting ions at a high concentration to form a plurality of regions isolated from each other, and measuring the current flowing between the isolated regions. CONSTITUTION:Phosphorus ions are implanted in a P-type semiconductor substrate 1 at a low concentration to provide a phosphorus doped layer 2. Pressure-sensitive tape 3 is affixed at the center of the semiconductor substrate 1 such that it extends transversely from one end to the other of the substrate 1 and that it divides the substrate surface into two sections. Arsenic ions are implanted in the semiconductor substrate 1 at a high concentration to provide a highly doped layer 4. Then, the tape is removed and the semiconductor substrate is washed. By annealing it, a large depression-type transistor having two highly doped regions 5 is obtained from the semiconductor substrate 1. When a certain voltage is applied between the highly doped regions 5, an amount of current corresponding to the amount of phosphorus ions implanted into the semiconductor substrate 1 flows therebetween. In this manner, the amount of implanted ions can be measured with high precision.
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