Method for producing an sgt-including semiconductor device

Abstract

A method for producing an SGT-including semiconductor device includes forming a gate insulating layer on an outer periphery of a Si pillar, forming a gate conductor layer on the gate insulating layer, and forming an oxide layer on the gate conductor layer. Then a hydrogen fluoride ion diffusion layer containing moisture is formed so as to make contact with the oxide layer and lie at an intermediate position of the Si pillar. A part of the oxide film in contact with the hydrogen fluoride ion diffusion layer is etched with hydrogen fluoride ions generated from hydrogen fluoride gas supplied to the hydrogen fluoride ion diffusion layer and an opening is thereby formed on the outer periphery of the Si pillar.

1 . A method of producing an SGT-including semiconductor device, the method comprising:
 a semiconductor-pillar-forming step of forming a semiconductor pillar on a substrate;   a first-impurity-region-forming step of forming a first impurity region below the semiconductor pillar;   a second-impurity-region-forming step of forming a second impurity region in the semiconductor pillar so that the second impurity region is distanced from and above the first impurity region;   a first-gate-insulating-layer-forming step of forming a first gate insulating layer on an outer periphery of the semiconductor pillar and at least a portion of the semiconductor pillar located between the first impurity region and the second impurity region;   a first-gate-conductor-layer-forming step of forming a first gate conductor layer on an outer periphery of the first gate insulating layer;   a first-insulating-layer-forming step of forming a first insulating layer so that the first insulating layer covers the semiconductor pillar and the first gate conductor layer;   a second-insulating-layer-forming step of forming a second insulating layer on the substrate and on an outer periphery of the first insulating layer, the second insulating layer being shorter than the semiconductor pillar;   a hydrogen-fluoride-ion-diffusion-layer-forming step of forming a hydrogen fluoride ion diffusion layer containing hydrogen-fluoride-ion and having a particular thickness on the second insulating layer and the first insulating layer;   a first-insulating-layer-etching step of etching a part of the first insulating layer on the hydrogen fluoride ion diffusion layer by using the hydrogen fluoride ions diffused from the hydrogen fluoride ion diffusion layer; and   a hydrogen-fluoride-ion-diffusion-layer-removing step of removing the hydrogen fluoride ion diffusion layer after the first-insulating-layer-etching step,   wherein an SGT is constituted by the first impurity region and the second impurity region that respectively function as a source and a drain or vice versa, the at least a portion of the semiconductor pillar located between the first impurity region and the second impurity region that functions as a channel between the drain and the source, the first gate insulating layer, and the first gate conductor layer.   
     
     
         2 . The method according to  claim 1 , which comprises generating the hydrogen-fluoride-ion in the hydrogen-fluoride-ion diffusion-layer by supplying hydrogen fluoride gas to the hydrogen-fluoride-ion diffusion-layer. 
     
     
         3 . The method according to  claim 1 , which further comprises:
 a third-impurity-region-forming step of forming a third impurity region on the second impurity region and in the semiconductor pillar, the third-impurity-region-form ing step being performed after the second-impurity-region-forming step and before the hydrogen-fluoride-ion-diffusion-layer-forming step,   wherein, in the hydrogen-fluoride-ion-diffusion-layer-forming step, the hydrogen fluoride ion diffusion layer is formed in a range that extends across where the second impurity region and the third impurity region are formed with respect to an upright direction of the semiconductor pillar; and   a first-gate-conductor-layer-etching step of etching the first gate conductor layer by using the first insulating layer as a mask, the first-gate-conductor-layer-etching step being performed after the hydrogen-fluoride-ion-diffusion-layer-removing step.   
     
     
         4 . The method according to  claim 3 , further comprising a first-gate-insulating-layer-etching step of etching the first gate insulating layer by using one or both of the first insulating layer and the first gate conductor layer as a mask, the first-gate-insulating-layer-etching step being performed after the first-gate-conductor-layer-etching step. 
     
     
         5 . The method according to  claim 4 , wherein:
 a top portion of the second insulating layer is positioned within a range where the second impurity region is formed in the semiconductor pillar with respect to the upright direction of the semiconductor pillar, and   the method further comprises a first-conductor-wiring-layer-forming step of forming a first conductor wiring layer so as to connect exposed portions of the second impurity region and the third impurity region in the semiconductor pillar, the first-conductor-wiring-layer-forming step being performed after the first-gate-insulating-layer-etching step.   
     
     
         6 . The method according to  claim 1 , wherein:
 a top portion of the hydrogen-fluoride-ion-diffusion-layer and a bottom portion of the hydrogen-fluoride-ion-diffusion-layer are positioned within a range where the first gate conductor layer is formed with respect to an upright direction of the semiconductor pillar, and   the method further comprises an insulating-film-partial-etching-step of etching a part of the first insulating film in contact with the hydrogen-fluoride-ion-diffusion-layer.   
     
     
         7 . The method according to  claim 6 , further comprising a second-conductor-wiring-layer-form ing step of forming a second conductor wiring layer connected to an exposed portion of the first gate conductor layer, the second-conductor-wiring-layer-forming step being performed after the hydrogen-fluoride-ion-diffusion-layer-removing step. 
     
     
         8 . The method according to  claim 1 , further comprising:
 a third-impurity-region-forming step of forming a third impurity region in the semiconductor pillar and on the second impurity region;   a fourth-impurity-region-forming step of forming a fourth impurity region above the third impurity region, the fourth impurity region containing a donor impurity or an acceptor impurity and having the same conductivity type as the third impurity region;   a second-gate-insulating-layer-forming step of forming a second gate insulating layer on the outer periphery of the semiconductor pillar and on at least a portion of the semiconductor pillar located between the third impurity region and the fourth impurity region, the second gate insulating layer being separated from the first gate insulating layer; and   a second-gate-conductor-layer-forming step of forming a second gate conductor layer on an outer periphery of the second gate insulating layer, the second gate conductor layer being separated from the first gate conductor layer.   
     
     
         9 . The method according to  claim 8 , wherein, in the hydrogen-fluoride-ion-diffusion-layer-forming step, the hydrogen fluoride ion diffusion layer is formed to be in contact with a part of the first insulating layer in an outer periphery direction so that a top portion of the hydrogen fluoride ion diffusion layer comes within a range of the third impurity region with respect to an upright direction of the semiconductor pillar and a bottom portion of the hydrogen fluoride ion diffusion layer comes within a range of the second impurity region with respect to the upright direction, and
 the method comprises:   a first-insulating-layer-etching step of etching a part of the first insulating layer on the hydrogen fluoride ion diffusion layer by using the hydrogen fluoride ions diffused from the hydrogen fluoride ion diffusion layer; and   a third-gate-insulating-layer-etching step of etching the first gate conductor layer by using the first insulating layer as a mask and then etching the first gate insulating layer by using one or both of the first insulating layer and the first gate conductor layer as a mask, the third-gate-insulating-layer-etching step being performed after the hydrogen-fluoride-ion-diffusion-layer-removing step.   
     
     
         10 . The method according to  claim 1 , wherein the first-impurity-region-forming step is performed after the first-gate-conductor-layer-forming step. 
     
     
         11 . The method according to  claim 1 , wherein:
 the method comprises a third-impurity-region-forming step of forming a third impurity region in the semiconductor pillar and on the second impurity region, the third impurity region containing a donor impurity or an acceptor impurity, the third-impurity-region-forming step being performed after the second-impurity-region-form ing step and before the hydrogen-fluoride-ion-diffusion-layer-form ing step,   wherein in the hydrogen-fluoride-ion-diffusion-layer-forming step, the hydrogen fluoride ion diffusion layer is formed so as to contact a part of the first insulating layer in an outer periphery direction so that a top portion of the hydrogen fluoride ion diffusion layer comes within a range of the third impurity region with respect to an upright direction of the semiconductor pillar and a bottom portion of the hydrogen fluoride ion diffusion layer comes within a range of the second impurity region with respect to the upright direction, and   the method comprises:   a second-insulating-layer-etching step of etching a part of the first insulating layer on the hydrogen fluoride ion diffusion layer by using the hydrogen fluoride ions diffused from the hydrogen fluoride ion diffusion layer; and   a third-gate-insulating-layer-etching step of etching the first gate conductor layer by using the first insulating layer as a mask and then etching the first gate insulating layer by using one or both of the first insulating layer and the first gate conductor layer as a mask, the third-gate-insulating-layer-etching step being performed after the hydrogen-fluoride-ion-diffusion-layer-removing step.