×

Semiconductor device and manufacturing method thereof

  • US 9,087,855 B2
  • Filed: 09/02/2014
  • Issued: 07/21/2015
  • Est. Priority Date: 05/12/2011
  • Status: Active Grant
First Claim
Patent Images

1. A method for manufacturing a semiconductor device, comprising the steps of:

  • forming an insulating layer including a first region having a first thickness and a second region having a second thickness smaller than the first thickness, the insulating layer including a trench including a side surface and a bottom surface, the bottom surface being overlapped with the second region;

    forming an oxide semiconductor film in contact with the bottom surface and the side surface of the trench and a top surface of the first region and forming at least a region in contact with the side surface and the bottom surface of the trench to include a crystal having a c-axis substantially perpendicular to a surface of the oxide semiconductor film under a heating condition;

    forming a source region and a drain region in contact with the top surface of the first region and an upper end corner portion where the top surface of the first region intersects the side surface of the trench and forming a channel formation region in contact with the side surface and the bottom surface of the trench by adding impurities;

    forming a source electrode layer and a drain electrode layer electrically connected to the source region and the drain region;

    forming a gate insulating layer over the oxide semiconductor film, the source electrode layer, and the drain electrode layer; and

    forming a gate electrode layer over the gate insulating layer, the gate electrode layer overlapping with the trench,wherein the source region and the drain region have higher impurity concentrations than the channel formation region.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×