Wide bandgap material in drift well of semiconductor device
The present disclosure generally relates to semiconductor devices including a material having a wide bandgap energy, or simply bandgap, located in a drift well of the semiconductor device. In an example, a semiconductor device includes a laterally-diffused metal-oxide-semiconductor (LDMOS) transistor. The LDMOS transistor includes a drain region, a source region, and a drift well. The drain region is disposed in a semiconductor material of a semiconductor substrate. The source region is disposed in the semiconductor material of the semiconductor substrate. The drift well is disposed laterally between the drain region and the source region. The drift well includes a wide bandgap material, and the wide bandgap material has a bandgap energy that is larger than a bandgap energy of the semiconductor material of the semiconductor substrate.
1 . A semiconductor device comprising:
a first laterally-diffused metal-oxide-semiconductor (LDMOS) transistor comprising:
a drain region disposed in a semiconductor material of a semiconductor substrate;
a source region disposed in the semiconductor material of the semiconductor substrate; and
a drift well disposed laterally between the drain region and the source region, the drift well including a wide bandgap material, the wide bandgap material having a bandgap energy that is larger than a bandgap energy of the semiconductor material of the semiconductor substrate,
wherein the wide bandgap material interfaces with the semiconductor material at a bottom surface and at linear sidewall surfaces.
2 . The semiconductor device of claim 1 , wherein the bandgap energy of the wide bandgap material is greater than 1.5 electron volt (eV).
3 . The semiconductor device of claim 1 , further comprising a local oxidation of silicon (LOCOS) structure disposed over the wide bandgap material.
4 . The semiconductor device of claim 1 , wherein the wide bandgap material includes silicon carbide (SiC).
5 . The semiconductor device of claim 4 , wherein:
a concentration of carbon in the silicon carbide (SiC) of the wide bandgap material increases from an interface between the semiconductor material and the wide bandgap material vertically along a direction to a peak carbon concentration; and
a concentration of carbon in the silicon carbide (SiC) of the wide bandgap material decreases vertically along the direction from the peak carbon concentration.
6 . The semiconductor device of claim 1 , wherein the wide bandgap material includes gallium nitride (GaN).
7 . The semiconductor device of claim 1 , wherein the wide bandgap material interfaces with the semiconductor material at a bottom surface and at curved sidewall surfaces.
8 . The semiconductor device of claim 1 , wherein the semiconductor material is silicon.
9 . The semiconductor device of claim 1 , wherein the drain region, the source region, and the drift well are respectively a first drain region, a first source region, and a first drift well, and further comprising a second LDMOS transistor comprising:
a second drain region disposed in the semiconductor material of the semiconductor substrate;
a second source region disposed in the semiconductor material of the semiconductor substrate; and
a second drift well disposed, at least in part, laterally between the second drain region and the second source region, the second drift well not including a wide bandgap material.
10 . A semiconductor device comprising:
a first laterally-diffused metal-oxide-semiconductor (LDMOS) transistor comprising:
a first gate electrode structure disposed over a first gate oxide layer and a first local oxidation of silicon (LOCOS) structure;
a first drain region disposed in a semiconductor material of a semiconductor substrate;
a first source region disposed in the semiconductor material of the semiconductor substrate, the first gate oxide layer and the first LOCOS structure being disposed laterally between the first drain region and the first source region; and
a first drift well disposed, at least in part, laterally between the first drain region and the first source region, the first drift well including a wide bandgap material, the wide bandgap material being disposed underlying the first LOCOS structure, the wide bandgap material having a bandgap energy that is larger than a bandgap energy of the semiconductor material of the semiconductor substrate,
wherein the wide bandgap material interfaces with the semiconductor material at a bottom surface and at linear sidewall surfaces.
11 . The semiconductor device of claim 10 , wherein the wide bandgap material includes silicon carbide (SiC), gallium nitride (GaN), or a combination thereof.
12 . The semiconductor device of claim 10 , further comprising a second LDMOS transistor comprising:
a second gate electrode structure disposed over a second gate oxide layer and a second LOCOS structure;
a second drain region disposed in the semiconductor material of the semiconductor substrate;
a second source region disposed in the semiconductor material of the semiconductor substrate, the second gate oxide layer and the second LOCOS structure being disposed laterally between the second drain region and the second source region; and
a second drift well disposed, at least in part, laterally between the second drain region and the second source region, the second drift well not including a wide bandgap material.
13 . A semiconductor device comprising:
a first laterally-diffused metal-oxide-semiconductor (LDMOS) transistor comprising:
a drain region disposed in a semiconductor material of a semiconductor substrate;
a source region disposed in the semiconductor material of the semiconductor substrate; and
a drift well disposed laterally between the drain region and the source region, the drift well including a wide bandgap material, the wide bandgap material having a bandgap energy that is larger than a bandgap energy of the semiconductor material of the semiconductor substrate,
wherein:
the wide bandgap material includes silicon carbide (SiC);
a concentration of carbon in the silicon carbide increases from an interface between the semiconductor material and the wide bandgap material vertically along a direction to a peak carbon concentration; and
a concentration of carbon in the silicon carbide decreases vertically along the direction from the peak carbon concentration.
14 . The semiconductor device of claim 13 , wherein the bandgap energy of the wide bandgap material is greater than 1.5 electron volt (eV).
15 . The semiconductor device of claim 13 , further comprising a local oxidation of silicon (LOCOS) structure disposed over the wide bandgap material.
16 . The semiconductor device of claim 13 , wherein the semiconductor material is silicon.