| 摘要 |
PROBLEM TO BE SOLVED: To provide a GaN-based semiconductor element which effectively becomes a normally-off type, by surelypulling its threshold to be positive, while keeping its on-resistance to be low. SOLUTION: In an FET-transistor 20, a buffer layer 2, a channel layer (undoped GaN layer) 3, and an electron supplying layer (undoped AlGaN layer) 4 are laminated on a sapphire substrate 1 in this order. An npn laminatedstructure 9 is formed in the source part on the electron supply layer 4, and a source electrode S is formed on the laminated structure 9. A drain electrode D is formed on the drain part of the electron supply layer 4, and an insulating film 8 is formed on an opening part 11, formed in the gate part of the electron supply layer. When a voltage equal to or grater than the threshold value is applied to a gate electrode G in the forward direction, inversion layers A and B are formed, resulting in a flow of the drain current. The threshold can be controlled, by varying the thickness or the impurity concentration of a p-type (In)GaN layer 6. The concentration of the electric field between the gate electrode G and the drain electrode D is regulated by a drift layer 12, and the breakdown voltage is improved. COPYRIGHT: (C)2010,JPO&INPIT |
