Elevationally-Extending Transistors, Devices Comprising Elevationally-Extending Transistors, and Methods of Forming a Device Comprising Elevationally-Extending Transistors

An elevationally-extending transistor comprising:

• an upper source/drain region, a lower source/drain region, and a channel region extending elevationally there-between;
• the channel region comprising an elevationally-elongated first material comprising an oxide semiconductor, the upper source/drain region and the first material having laterally-coincident laterally-outer sidewalls, the lower source drain region being an integral portion of a source line, the source line consisting of an elemental metal and conductively doped silicon, the elemental metal being over the conductively doped silicon with the elemental metal and the conductively doped silicon each being patterned, the source line having sidewalls extending vertically along the conductively doped silicon and the elemental metal, the conductively doped silicon and the elemental metal each extending an entirety of a length of the source line;
• a transistor gate over two opposing sides of the channel region, a gate insulator over individual of the two opposing sides of the channel region laterally between the channel region and the transistor gate, the gate insulator extending along lateral sidewalls of the upper source/drain region;
• and
• an elevationally-elongated second material being aside the channel-region-first material, the second material having greater Eg than the first material, the first material extending laterally across and directly under a bottom of the second material.