VTFET Bottom Spacer Layer for Gate Junction Control

The patent introduces a bottom spacer layer as an intermediary element positioned between the gate structure and the bottom source/drain. This spacer layer acts as a mediator that physically separates the gate from the source/drain region, thereby reducing parasitic capacitance while still allowing the gate to control the channel effectively. The spacer layer is formed with a specific thickness to optimize the balance between capacitance reduction and device performance.

The patent extends the gate structure vertically by adding the bottom spacer layer, creating a multi-dimensional gate configuration. Instead of only adjusting the horizontal position of the gate, the solution introduces a vertical dimension through the spacer layer, allowing the gate to extend into the spacer gap region. This dimensional extension enables better control over the electric field distribution and parasitic capacitance without compromising the gate's control over the channel.

The patent segments the gate structure into two distinct parts: the main gate layer and the bottom spacer layer. This segmentation allows each component to be optimized independently for its specific function. The bottom spacer layer can be precisely controlled in thickness and position to ensure uniform gate junction positioning across different devices, while the main gate layer maintains its primary control function. This segmentation simplifies the manufacturing process by allowing sequential formation and optimization of each segment.

The patent forms the bottom spacer layer as a preliminary structure before completing the gate formation process. This preliminary action establishes a reference framework that guides subsequent gate positioning and ensures uniformity. By pre-forming the spacer layer with controlled dimensions, the patent creates a template that automatically ensures consistent gate junction positioning across multiple devices, reducing the need for complex post-processing adjustments.