Semiconductor device having a silicon layer in a gate electrode
AssigneeElpida Memory, Inc.
InventorsSatoru Yamada, Ryo Nagai
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Abstract
A CMOS device includes a silicon substrate, a gate insulating film, and a gate electrode including a silicon layer doped with boron and phosphorous, a tungsten nitride layer and a tungsten layer. A ratio of a maximum boron concentration to a minimum boron concentration in a boron concentration profile across the thickness of the silicon layer is not higher than 100. The CMOS device has a lower NBTI (Negative Bias Temperature Instability) degradation.
Claims11
A semiconductor device comprising:
- a semiconductor substrate;
- a gate insulating film formed on said semiconductor substrate;
- and
- a gate electrode including a silicon layer as a bottom layer formed on said gate insulating film, said silicon layer being doped with phosphorous and boron,
- wherein a ratio of a maximum boron concentration to a minimum boron concentration in a boron concentration profile across a thickness of said silicon layer is not higher than 100.
A method for forming a semiconductor device comprising the consecutive steps of:
- consecutively depositing a gate insulating film and a silicon layer on a semiconductor substrate;
- implanting boron into said silicon layer;
- diffusing said implanted boron by heat-treating said silicon layer;
- implanting phosphorous into said silicon layer;
- diffusing at least said implanted phosphorous by heat-treating said silicon layer;
- and
- patterning said silicon layer by using a dry etching technique.
A method for forming a semiconductor device comprising the consecutive steps of:
- consecutively depositing a gate insulating film and a silicon layer on a semiconductor substrate;
- implanting phosphorous into said silicon layer;
- diffusing said implanted phosphorous by heat-treating said silicon layer;
- implanting boron into said silicon layer;
- diffusing at least said implanted boron by heat-treating said silicon layer;
- and
- patterning said silicon layer by using a dry etching technique.
Dependencies are inferred from the claim text.