Semiconductor device having trench capacitors and method for making the trench capacitors

A method of making of a trench capacitor comprising:

• forming a trench on a surface of a semiconductor substrate having a first conductivity type;
• forming a first insulating film on a side wall of the trench;
• burying a semiconductor film in the trench on the first insulating film;
• etching the first insulating film and the semiconductor film located in an upper part of the trench so as to expose a first side wall of the trench;
• depositing a second insulating film on the first side wall of the trench using a low pressure CVD method without thermal oxidation;
• etching the first insulating film and the semiconductor film so as to expose a second side wall at a lower position than the first side wall of the trench;
• etching the second side wall of the trench so as to form a third side wall, using the second insulating film as a mask;
• forming a plate electrode of a second conductivity type different from the first conductivity type on the third side wall;
• forming a capacitor insulating film on the plate electrode;
• and
• burying a storage electrode in the capacitor insulating film and in the second insulating film within the trench.