Memories having a charge storage node at least partially located in a trench in a semiconductor substrate and electrically coupled to a source/drain region formed in the substrate

An integrated circuit comprising:

• a semiconductor substrate comprising a trench therein;
• a memory charge storage node at least partially located in the trench;
• and
• a transistor comprising a first source/drain region in the semiconductor substrate, the first source/drain region being electrically coupled to the charge storage node, wherein in a planar vertical cross section the trench has a first side and a second side opposite to the first side, and the first source/drain region is present at the first side of the trench but not at the second side of the trench;
• wherein the charge storage node has a protrusion on its top surface at the first side of the trench, the protrusion being adjacent to the first source/drain region, and the charge storage node also has a top surface portion laterally adjacent to said protrusion and present at the second side of the trench;
• wherein in said cross section the trench sidewall has a substantially straight semiconductor sidewall portion on the second side of the trench, and the sidewall portion rises from below the top surface portion of the charge storage node to a position above the top surface portion of the charge storage node on the second side of the trench.

An integrated circuit comprising:

• a semiconductor substrate comprising a trench therein;
• a memory charge storage node at least partially located in the trench;
• a transistor comprising a first source/drain region in the semiconductor substrate, the first source/drain region being electrically coupled to the charge storage node, wherein in a planar vertical cross section the trench has a first side and a second side opposite to the first side, and the first source/drain region is present at the first side of the trench but not at the second side of the trench;
• and
• a dielectric between the trench sidewall and the charge storage node, wherein in said cross section the dielectric has a dielectric portion on the second side of the trench, said dielectric portion being thicker in said cross section than the dielectric on the first side of the trench when a thickness is measured normally to the trench sidewall, the trench sidewall having a substantially straight semiconductor sidewall portion rising from below the bottom of said dielectric portion to a position above the bottom of said dielectric portion in said cross section.