Garnet compound, oxide sintered compact, oxide semiconductor thin film, thin film transistor, electronic device and image sensor

Abstract

A sintered oxide contains In element, Y element, and Ga element at respective atomic ratios as defined in formulae (1) to (3) below, 0.80≤In/(In+Y+Ga)≤0.96  (1), 0.02≤Y/(In+Y+Ga)≤0.10  (2), and 0.02≤Ga/(In+Y+Ga)≤0.10  (3), and Al element at an atomic ratio as defined in a formula (4) below, 0.005≤Al/(In+Y+Ga+Al)≤0.07  (4), where In, Y, Ga, and Al in the formulae represent the number of atoms of the In element, Y element, Ga element, and Al element in the sintered oxide, respectively.

1 . An oxide semiconductor thin-film comprising:
 In element, Y element, Ga element, and Al element at respective atomic ratios as defined in formulae (1-7) to (1-9) and (1-10(b)) below,
   0.80≤In/(In+Y+Ga)≤0.90  (1-7),
 
   0.03≤Y/(In+Y+Ga)≤0.10  (1-8),
 
   0.02≤Ga/(In+Y+Ga)≤0.15  (1-9), and
 
   0.005≤Al/(In+Y+Ga+Al)≤0.0259  (1-10b),
 
   where In, Y, Ga, and Al in the formulae represent the number of atoms of the In element, Y element, Ga element, and Al element in the oxide semiconductor thin-film, respectively.   
     
     
         2 . The oxide semiconductor thin-film according to  claim 1 , further comprising Ga element at an atomic ratio as defined in a formula (1-11) below,
   0.02≤Ga/(In+Y+Ga)≤0.10  (1-11).
   
     
     
         3 . The oxide semiconductor thin-film according to  claim 1 , further comprising an oxide of a positive tetravalent or more polyvalent metal element X at an atomic ratio defined by a formula (1-12) below,
   0.00005≤X/(In+Y+Ga+Al+X)≤0.005  (1-12),
   where X represents the number of atoms of the X element in the oxide semiconductor thin-film.   
     
     
         4 . The oxide semiconductor thin-film according to  claim 1 , wherein the oxide semiconductor thin-film comprises a Bixbyite crystalline phase represented by In 2 O 3 . 
     
     
         5 . The oxide semiconductor thin-film according to  claim 4 , wherein a lattice constant of the Bixbyite crystalline phase represented by In 2 O 3  is 10.083×10 −10  m or less. 
     
     
         6 . A thin-film transistor comprising the oxide semiconductor thin-film according to  claim 1 . 
     
     
         7 . An electronic device comprising the thin-film transistor according to  claim 6 . 
     
     
         8 . The oxide semiconductor thin-film according to  claim 1 , wherein
 the atomic ratio of the Al element [Al/(In+Y+Ga+Al)] in the formula (1-10b) is in a range from 0.01 to 0.025.