US 12,230,675 B2
Planar SiC MOSFET with retrograde implanted channel
Marco Bellini, Schlieren (CH); and Lars Knoll, Hägglingen (CH)
Assigned to Hitachi Energy Ltd, Zürich (CH)
Appl. No. 17/631,711
Filed by Hitachi Energy Ltd, Zürich (CH)
PCT Filed Jul. 31, 2020, PCT No. PCT/EP2020/071698
§ 371(c)(1), (2) Date Jan. 31, 2022,
PCT Pub. No. WO2021/019086, PCT Pub. Date Feb. 4, 2021.
Claims priority of application No. 19189649 (EP), filed on Aug. 1, 2019.
Prior Publication US 2022/0320290 A1, Oct. 6, 2022
Int. Cl. H01L 29/10 (2006.01); H01L 21/04 (2006.01); H01L 29/16 (2006.01); H01L 29/66 (2006.01); H01L 29/739 (2006.01); H01L 29/78 (2006.01)
CPC H01L 29/1045 (2013.01) [H01L 21/046 (2013.01); H01L 29/1608 (2013.01); H01L 29/66068 (2013.01); H01L 29/7395 (2013.01); H01L 29/7802 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A silicon carbide (SiC) planar transistor device comprising:
a SiC semiconductor substrate of a first charge type having a top surface and a bottom surface;
a SiC epitaxial layer of the first charge type formed on the top surface of the SiC semiconductor substrate, the SiC epitaxial layer having a top surface;
a source structure of the first charge type formed in the top surface of the SiC epitaxial layer, the source structure having a top surface;
a drain structure of the first charge type formed on the bottom surface of the SiC semiconductor substrate;
a gate structure comprising a gate dielectric and a gate runner, wherein the gate dielectric covers at least part of the source structure and the gate runner;
a channel region of a second charge type located in vertical direction below the gate structure and adjacent to the source structure, wherein a doping profile of the second charge type of the channel region comprises a first region and a second region;
wherein the first region has a constant doping concentration in a range of 2×1017 cm-3 to 3×1018 cm−3 and is located in a vertical direction below to the gate dielectric with a depth between 50 nm to 250 nm from the top surface of the SiC epitaxial layer;
wherein the second region has a Pearson-Type-IV-like distributed doping concentration with a peak doping concentration in a range of 1.5×108 cm−3 to 8×1018 cm−3 and is located in a vertical direction below and adjacent to the first region with the peak position of the Pearson-Type-IV-like distribution in a range of 300 nm to 500 nm from the top surface of the SiC epitaxial layer; and
wherein the channel has a length in a range of 50 nm to 250 nm.