Hydrogen terminated on Si surface actively contributes to the succeeding selective chemical vapor deposition (CVD) of Al using dimethylaluminum hydride \DMAH, (CH3)2AIH] and H2. In this article, we describe our recent progress of area-selective Al CVD on H-terminated Si surface. By thermal decomposition, 0.3µm-diam./1µm-deep SiO2-via-holes on Si surface are filled with the selective single-crystal Al. As a selective growth mechanism of Al on Si, we have proposed a “surface electrochemical reaction” model. The most significant point is (1) catalytic contribution of surface free–electrons, (2) surface terminated–H, and (3) selective reaction between terminated–H and CH3–radical of DMAH. Recently, we have performed area–selective deposition of Al on Si by patterning the monolayer terminated–H, i.e. atomic hydrogen resist process. The terminated–H on Si is intentionally desorbed by the electron beam exposure. The activated Si surface is oxidized in the air environment. Then, single–crystal Al has been successfully deposited on the remaining H–terminated area and not deposited on nanometer–thick oxidized area formed by the electron beam lithography.