Semiconductor device and method of manufacturing the same
A semiconductor device including an IE-type trench gate IGBT requires to be improved in IE effect to reduce on voltage. The semiconductor device includes a trench gate electrode or a trench emitter electrode between an active cell region and an inactive cell region. The trench gate electrode and the trench emitter electrode are provided across the inactive cell region.
1. A semiconductor device, comprising:
a semiconductor substrate having a first main surface and a second main surface;
a drift region provided in the semiconductor substrate and having a first conductivity type;
a cell region provided over the first main surface;
a large number of unit cell regions provided in the cell region in planar view;
wherein each of the unit cell regions includes:
an active cell region provided from over the first main surface to the inside of the drift region;
a trench gate electrode and a trench emitter electrode in a pair of trenches provided in a surface of the first main surface so as to sandwich the active cell region from both sides in planar view;
a second-conductivity-type body region having a conductivity type opposite to the first conductivity type and provided in a surface region of the drift region on a side close to the first main surface;
inactive cell regions provided adjacent to two sides of the active cell region so as to sandwich the active cell region from the two sides in planar view with the trench gate electrode and the trench emitter electrode as boundaries;
a first-conductivity-type emitter region having the same conductivity type as the first conductivity type and provided in a surface region of the second-conductivity-type body region on a side close to the first main surface;
a contact hole in contact with the trench emitter electrode and the first-conductivity-type emitter region;
a first-conductivity-type hole barrier region provided in the drift region below the second-conductivity-type body region in the active cell region, and having the same conductivity type as the first conductivity type and having an impurity concentration higher than an impurity concentration of the drift region and lower than an impurity concentration of the first-conductivity-type emitter region; and
a second-conductivity-type floating region having a conductivity type opposite to the first conductivity type and provided in a surface region on a side close to the first main surface in the inactive cell region.
2. The semiconductor device according to claim 1 , wherein the second-conductivity-type floating region covers lower ends of the pair of trenches, and has a depth deeper than a depth of each of the trenches having the trench gate electrode and the trench emitter electrode.
3. The semiconductor device according to claim 1 , further comprising:
a metal collector electrode provided over the second main surface of the semiconductor substrate;
a second-conductivity-type collector region having the conductivity type opposite to the first conductivity type and provided in the second main surface of the semiconductor substrate;
a first-conductivity-type field stop region provided on a side close to the second main surface of the drift region so as to be in contact with the second-conductivity-type collector region, and having the same conductivity type as the first conductivity type and having an impurity concentration higher than an impurity concentration of the drift region; and
a second-conductivity-type high-concentration collector contact region provided on a side close to the metal collector electrode of the second-conductivity-type collector region, and having an impurity concentration higher than an impurity concentration of the second-conductivity-type collector region.