| 摘要 |
<p>A P<+> layer 12 is formed on the lower surface of an N<-> substrate 10, and recesses 40 are defined in the upper surface of the N<-> substrate 10. Then, P<+> gate regions 32 and bottom gate regions 34 are formed in side walls 42 and bottoms 44 of the recesses 40. The N<-> substrate 10 and an N<-> substrate 20 are ultrasonically cleaned to remove impurities therefrom, then cleaned by pure water, and dried by a spinner. Then, while lands 14 on the upper surface of the N<-> substrate 10 are being held against the surface of the N<-> substrate 20, the N<-> substrates 10, 20 are joined to each other by heating them at 800 DEG C in a hydrogen atmosphere. <IMAGE></p> |
