Semiconductor device and method for manufacturing the same

A semiconductor device, comprising:

• a first electrode;
• a first semiconductor region located on the first electrode, the first semiconductor region being electrically connected with the first electrode, the first semiconductor region being of a first conductivity type;
• a gate electrode located on the first semiconductor region with a gate insulating layer interposed;
• a second semiconductor region facing the gate electrode via the gate insulating layer in a second direction perpendicular to a first direction, the first direction being from the first electrode toward the first semiconductor region, the second semiconductor region being of a second conductivity type, the second semiconductor region including
• a first portion, and
• a second portion located on the first portion, the second portion having a higher second-conductivity-type impurity concentration than the first portion;
• a third semiconductor region located on the second semiconductor region, the third semiconductor region being of the first conductivity type;
• and
• a second electrode electrically connected with the second and third semiconductor regions, the second electrode including a contact part arranged with the third semiconductor region in the second direction and located on the second semiconductor region,
• a length of a first region being less than 0.5 times a length of a second region,
• the first region being a region in which an impurity concentration of an impurity concentration distribution of the second conductivity type is within a range of 0.1 times to 0.001 times a maximum value of the impurity concentration when the impurity concentration distribution is measured along the second direction from the second portion toward the gate insulating layer,
• the second region being a region in which the impurity concentration of the impurity concentration distribution is within a range of 0.1 times to 0.001 times a maximum value of the impurity concentration when the impurity concentration distribution is measured along the first direction from an interface between the second portion and the contact part toward the first portion.

A method for manufacturing a semiconductor device,

• the device including a structure body,
• the structure body including:
• a first semiconductor region of a first conductivity type;
• a conductive layer located on the first semiconductor region with an insulating layer interposed;
• a second semiconductor region facing the conductive layer via the insulating layer in a second direction perpendicular to a first direction, the first direction being from the first semiconductor region toward the conductive layer, the second semiconductor region being of a second conductivity type;
• and
• a third semiconductor region located on the second semiconductor region, the third semiconductor region being of the first conductivity type,
• the method comprising:
• forming an opening in the structure body by removing a portion of the second semiconductor region and a portion of the third semiconductor region;
• ion-implanting at least one selected from the group consisting of carbon, germanium, antimony, indium, argon, and silicon into the second semiconductor region via the opening at a first angle with respect to the first direction;
• and
• ion-implanting a second-conductivity-type impurity into the second semiconductor region via the opening at a second angle with respect to the first direction, the second angle being less than the first angle.