Patent ID: 8058141

Claim:
A method for fabricating a transistor, the method comprising the steps of: forming a first etch mask on a silicon substrate having an active area and an isolation area so as to expose the isolation area; forming a trench by etching the exposed isolation area of the silicon substrate; forming a first insulation layer having a stacked structure of a first oxide layer on a surface of the trench and a nitride layer on the first oxide layer and the first etch mask such that the first oxide layer is underneath the nitride layer and the first oxide layer is directly on the trench; forming a second insulation layer including a second oxide layer on the first insulation layer such that the trench is filled with the second insulation layer; removing a portion of the second insulation layer and a portion of the first insulation layer until the first etch mask is exposed to an exterior; forming a trench type isolation layer on the isolation area of the silicon substrate by removing the first etch mask; forming a second etch mask on an entire surface of the silicon substrate including the isolation layer such that a channel area to be formed in the active area is exposed through the second etch mask; etching the exposed channel area formed in the active area of the silicon substrate, thereby forming a recess having a depth smaller than a depth of the trench; performing an etching process with respect to a resultant substrate structure, thereby removing a predetermined portion of the first insulation layer formed at a lateral portion of the second insulation layer in the isolation layer, which is exposed through the recess, in such a manner that a remaining part of the first insulation layer is positioned lower than a bottom of the recess; and forming a gate in the recess by sequentially depositing a gate insulation layer and a gate conductive layer in the recess such that the first oxide layer, the nitride layer and the gate insulation layer form a triple contiguous layer immediately between an adjacent portion of the insulation layer of the trench and an adjacent portion of the channel.