METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a method for manufacturing semiconductor device which makes possible to solve the problems of: a defect of a through-hole remaining unopened attributed to crystal grains; short circuit between lower electrodes owing to the variations in bore diameter and separation width; and the restriction imposed on the capacitance of a cell capacitor, and the drop in operation speed of a semiconductor device, which are attributed to a through-hole tapering toward its lower end.SOLUTION: A method for manufacturing a semiconductor device 1a comprises the steps of: forming an amorphous silicon film 10 on an upper surface of a base layer 7; forming an amorphous silicon film 11 on an upper surface of the amorphous silicon film 10; and providing through-holes 20 in the amorphous silicon films 10 and 11 by etching. The step of forming the amorphous silicon film 11 is arranged to include the substeps of: forming a first part 11a of the amorphous silicon film 11 to include impurities at a concentration higher than the concentration of impurities in the amorphous silicon film 10; and thereafter, forming a second portion 11b of the amorphous silicon film 11 to include impurities at a concentration lower than that in the first part 11a. 【課題】結晶粒によって発生する貫通孔の非開孔性欠陥、孔径や分離幅にバラつきが生ずることによる下部電極間の短絡、貫通孔の下部が細くなってしまうことによるセルキャパシタ容量の制限及び半導体装置の動作速度の低下、といった諸問題を解決する半導体装置の製造方法を提供する。【解決手段】半導体装置１ａの製造方法は、ベース層７の上面に非晶質シリコン膜１０を形成する工程と、非晶質シリコン膜１０の上面に非晶質シリコン膜１１を形成する工程と、エッチングにより、非晶質シリコン膜１０，１１に複数の貫通孔２０を設ける工程とを備え、非晶質シリコン膜１１を形成する工程は、非晶質シリコン膜１０の不純物濃度より高い濃度で不純物を含有するように非晶質シリコン膜１１の第１の部分１１ａを形成した後、第１の部分１１ａの不純物濃度より低い濃度で不純物を含有するように非晶質シリコン膜１１の第２の部分１１ｂを形成するよう構成される。【選択図】図２