as the heavily doped substrate?作用和含义

The semiconductor wafer with epitaxial layer of the same polarity as the heavily doped substrate has the opposite polarity to form the p-n junction at the top of the wafer.

The semiconductor wafer with epitaxial layer of the same polarity as the heavily doped substrate has the opposite polarity to form the p-n junction at the top of the wafer.

带有与高掺杂衬底相同极性的外延层的半导体晶片具有相反极性，以在晶片顶部形成pn结。

带有与高掺杂衬底相同极性的外延层的半导体晶片具有相反极性，用以在所述晶片顶部形成p-n结。
注意the same... as...

谢谢楼上!