Patent ID: 8492226
Filing Date: 2013-07-23
Classification: H01L

Abstract:
1. A method of forming a device comprising: providing a substrate defined with a device region; forming a buried doped region in the substrate in the device region; forming a trench having upper and lower portions of different widths in the substrate in the device region; forming sidewall spacers on sidewalls of the upper portion of the trench, leaving a portion of the upper portion unfilled; forming a drain connector in the trench; removing the sidewall spacers, the removal of the sidewall spacer leaves a gap between the sidewalls of the trench and exposes a portion of the drain connector; forming a gate in the upper portion of the trench in the substrate in the device region, wherein a channel of the device is disposed on a sidewall of the upper portion of the trench, the buried doped region is disposed below the gate, wherein a distance from the buried doped region to the channel is a drift length L forming a surface doped region adjacent to the gate.