| 摘要 |
PROBLEM TO BE SOLVED: To fairly decrease a manufacture step, reduce all process times, and enhance device performance characteristic by a method wherein, before a second layer of an undoped material is vapor-deposited on a first layer containing a dopant, the first layer is not brought into contact with an air. SOLUTION: A silicon nitride layer 102 is vapor-deposited on a silicon wafer 100, and a trench 104 is formed by plasma-etching therein. Next, a first arsenic- doped glass layer 106 is formed by LPCVD of arsenic-doped glass by use of tetraethyl arsenate within the trench 104 and on the silicon nitride layer 102. Next, a second layer 108 of glass undoped by LPCVD is vapor-deposited on the first glass layer 106 by use of ortho-tetraethyl silicate. Incidentally, before the undoped second glass layer 108 is formed, the arsenic-doped first glass layer 106 must not be exposed to an element reacting involuntarily with arsenic therein, in particular an air. |
