Patent ID: 9419055
Filing Date: 2016-08-16
CPC Classification: H01L

Claim Text:
1. A semiconductor device, comprising: an active pillar extending from a substrate in a first direction and including a source and a drain, wherein the source and the drain are arranged in the first direction; a channel region formed in the active pillar and between the source and the drain; a lightly doped drain (LDD) region formed in the active pillar and between the drain and the channel region; a gate insulating layer formed over a sidewall of the active pillar in a second direction, wherein the second direction is perpendicular to the first direction; a first gate electrode formed over the gate insulating layer in the second direction, surrounding the LDD region and the drain, and having a first work function; and a second gate electrode formed over the gate insulating layer in the second direction, surrounding the channel region, and having a second work function, wherein the second work function is higher than the first work function, wherein a total thickness of the second gate electrode is larger than a total thickness of the first gate electrode, wherein each of the total thickness of the second gate electrode and the total thickness of the first gate electrode is measured only in the second direction.