Fabrication methods of forming annular vertical SI etched channel MOS devices
A method, according to one embodiment, includes: forming an annular cylindrical channel from a single block of electrically conductive material; forming an oxide layer over exposed surfaces of the annular cylindrical channel and exposed surfaces of the block of electrically conductive material; removing a portion of the oxide layer from an exterior base of the annular cylindrical channel, thereby forming a source contact recess which surrounds the base of the annular cylindrical channel; ion-implanting the exposed electrically conductive material substrate at a base of the source contact recess; and depositing a silicide material in the source contact recess, thereby forming a source contact tab. Moreover, other systems and methods are also described in additional embodiments herein which provide various different improved processes of forming the annular cylindrical channels, the source contact tabs, and/or the cylindrical pillar gate contacts for vertical transistor structures in comparison to conventional surface transistor structures.
1. A method of forming a cylindrical vertical transistor, comprising:
forming an annular cylindrical channel from a single block of electrically conductive material;
forming an oxide layer over exposed surfaces of the annular cylindrical channel and exposed surfaces of the block of electrically conductive material;
removing a portion of the oxide layer from an exterior base of the annular cylindrical channel, wherein removing the portion of the oxide layer forms a source contact recess which surrounds the base of the annular cylindrical channel;
ion-implanting the exposed electrically conductive material substrate at a base of the source contact recess;
depositing a silicide material in the source contact recess, thereby forming a source contact tab;
depositing a gate mask over a majority of the oxide layer and the source contact tab;
forming a recess by removing a portion of the oxide layer, a portion of the annular cylindrical channel, a portion of the annular oxide layer, and a portion of the cylindrical pillar gate contact;
depositing an electrically insulating material over exposed surfaces of the oxide layer, the annular cylindrical channel, the annular oxide layer, and the cylindrical pillar gate contact in the formed recess;
removing the electrically insulating material from the exposed surfaces of the cylindrical pillar gate contact; and
depositing a third electrically conductive material in the recess and on the electrically insulating material,
wherein the third electrically conductive material deposited in the recess forms a gate contact tab.
2. The method as recited in claim 1 , wherein the third electrically conductive material includes TaN.
3. The method as recited in claim 1 , wherein the third electrically conductive material is non-magnetic.
4. The method as recited in claim 1 , wherein the portion of the annular cylindrical channel, the portion of the annular oxide layer, and the portion of the cylindrical pillar gate contact are removed using an ion beam trench etching process.
5. The method as recited in claim 1 , comprising:
forming a magnetic tunnel junction (MTJ) sensor stack above the annular cylindrical channel, such that a first end of the MTJ sensor stack is electrically coupled to an upper portion of the annular cylindrical channel.
6. A magnetic device, comprising:
a plurality of cylindrical vertical transistors formed using the method as recited in claim 5 ,
wherein a second end of the MTJ sensor stack in each of the cylindrical vertical transistors is coupled to a common drain line,
wherein the source contact tab in each of the cylindrical vertical transistors is coupled to a common source line,
wherein the gate contact tab in each of the cylindrical vertical transistors is coupled to a common word line.