Patent ID: 9685563
Date: 2017-06-20
CPC Classifications: H01L

Claim:
1. A semiconductor device comprising: a first oxide semiconductor film; a second oxide semiconductor film over the first oxide semiconductor film; a source electrode over the second oxide semiconductor film; a drain electrode over the second oxide semiconductor film; a metal oxide film over the second oxide semiconductor film, the source electrode, and the drain electrode; and a gate electrode overlapping with the second oxide semiconductor film with a gate insulating film interposed therebetween, wherein the metal oxide film comprises an element M (M represents Ti, Ga, Y, Zr, La, Ce, Nd, or Hf) and Zn, and wherein the metal oxide film comprises a portion where x/(x+y) is greater than 0.67 and less than or equal to 0.99 when an atomic ratio of the element M to Zn in a target is represented by M:Zn=x:y.