Method of making a semiconductor memory device

A method for manufacturing a semiconductor memory device on a semiconductor substrate comprising:

• forming first and second pairs of substantially parallel trenches in said semiconductor substrate, said first pair of trenches arranged substantially orthogonal to said second pair of trenches thereby defining a rectangular block in said substrate;
• forming first and second capacitive elements on portions of said trenches, each of said capacitive elements including an electrode layer embedded in said portions of said trenches;
• forming first and second gate regions spaced apart on a major surface of said substrate along opposite side wall surfaces of said block formed by said parallel trenches, said first and second gate regions including respective first and second gate electrodes formed in said trenches along said opposite side wall surfaces and extending out of said trenches, parallel to said substrate, said first and second gate regions being electrically isolated from each other and adjacent said first and second capacitive elements, respectively;
• and
• forming a source/drain region common to said first and second gate regions on said major surface.

A method for manufacturing a semiconductor memory device on a semiconductor substrate comprising:

• forming a substantially rectangular trench in said semiconductor substrate forming a substantially rectangular block in said substrate;
• forming a passive element region on a bottom portion of said trench adjacent said opposite side walls of said trench;
• forming a pair of gate regions on a major surface of said semiconductor along upper portions of opposite side walls of said block, said pair of gate regions including respective gate electrodes formed in said trench along said opposite side wall surfaces and extending out of said trench, parallel to said substrate, each gate region being formed electrically isolated from each other;
• and
• forming a source/drain region common to said pair of gate regions on said major surface.

A method for manufacturing a semiconductor memory device on a semiconductor substrate comprising:

• forming a substantially rectangular trench in said semiconductor substrate forming a substantially rectangular block in said substrate;
• forming a passive element region on a bottom portion of said trench adjacent said opposite side walls of said trench;
• forming a pair of gate regions on a major surface of said semiconductor along upper portions of opposite side walls of said block, said pair of gate regions including respective gate electrodes formed in said trench along said opposite side wall surfaces and extending out of said trench, parallel to said substrate, each gate region being formed electrically isolated from each other;
• and
• forming a source/drain region common to said pair of gate regions on said major surface;
• wherein
• said step of forming said passive element region comprises the step of:
• forming first and second capacitive elements on portions of said trench adjacent said first and second gate regions, respectively, comprising the steps of
• (a) forming a first electrode layer on said wall surfaces of the trench at a position corresponding to an insulating layer,
• (b) forming said insulating layer on said first electrode layer on the wall surface of the trench, and
• (c) forming a second electrode layer embedded in said portions of said trench.