# US 2014/0151791 A1 · Semiconductor device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0151791 A1 - Document ID: US20140151791A1 - Status: Published application - Kind: A1 - Application number: 13/899,916 - Filed: 2013-05-22 - Published: 2014-06-05 - Earliest claimed: 2012-05-29 - Assignees: Elpida Memory, Inc. - Applicants: Elpida Memory, Inc. - Inventors: Kanta SAINO - Web page: https://patentgrep.com/patent/US20140151791A1 ## CPC - H10D 64/691: {comprising metallic compounds, e.g. metal oxides or metal silicates (insulators comprising nitrogen H10D64/693)} - H10B 12/0335: {Making a connection between the transistor and the capacitor, e.g. plug} - H10B 12/053: {the transistor being at least partially in a trench in the substrate (vertical transistor in combination with a capacitor formed in a substrate trench H10B12/0383)} - H10B 12/09: {with simultaneous manufacture of the peripheral circuit region and memory cells} - H10B 12/315: {with the capacitor higher than a bit line} - H10B 12/482: {Bit lines} - H10B 12/488: {Word lines} - H10B 43/40: characterised by the peripheral circuit region - H10D 64/685: {being perpendicular to the channel plane} - H10D 89/10: Integrated device layouts - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10B: ELECTRONIC MEMORY DEVICES ## Abstract A semiconductor device comprises: a memory cell region having a first transistor and a peripheral circuit region having a second transistor. The first transistor has a first source electrode and a first drain electrode, a first buried gate insulating film which is formed along an inner wall of a trench and whose relative dielectric constant is higher than a relative dielectric constant of silicon oxide, and a buried gate electrode. The second transistor has a second source electrode and a second drain electrode, a first on-substrate gate insulating film whose relative dielectric constant is higher than a relative dielectric constant of silicon oxide, and an on-substrate gate electrode. A first Hf content percentage, which is a content percentage of hafnium in the first buried gate insulating film, is different from a second Hf content percentage, which is a content percentage of hafnium in the first on-substrate gate insulating film. ## Claims ### Claim 1 A semiconductor device, comprising: a memory cell region having a first transistor, and a peripheral circuit region which is formed around said memory cell region and has a second transistor, on a semiconductor substrate; wherein said first transistor has: a first source electrode and a first drain electrode which are formed on said semiconductor substrate, a first buried gate insulating film which is formed along an inner wall of a trench formed in said semiconductor substrate between said first source electrode and said first drain electrode and whose relative dielectric constant is higher than a relative dielectric constant of silicon oxide, and a buried gate electrode which is formed in said trench on said first buried gate insulating film, comprises metal and functions as a word line; and said second transistor has: a second source electrode and a second drain electrode which are formed on said semiconductor substrate, a first on-substrate gate insulating film which is formed on a surface of said semiconductor substrate between said second source electrode and said second drain electrode and whose relative dielectric constant is higher than a relative dielectric constant of silicon oxide, and an on-substrate gate electrode which is formed on said first on-substrate gate insulating film and comprises metal; said first buried gate insulating film and said first on-substrate gate insulating film comprising a compound containing hafnium (hereinafter referred to as “hafnium-containing compound”.); wherein a first Hf content percentage, which is a content percentage of hafnium in said first buried gate insulating film, is different from a second Hf content percentage, which is a content percentage of hafnium in said first on-substrate gate insulating film. ### Claim 2 (depends on 1) The semiconductor device according to claim 1, wherein said first Hf content percentage is lower than said second Hf content percentage. ### Claim 3 (depends on 1) The semiconductor device according to claim 1, wherein said first Hf content percentage is lower than said second Hf content percentage by 10 atm % or more. ### Claim 4 (depends on 1) The semiconductor device according to claim 1, wherein said hafnium-containing compound in said first buried gate insulating film is not crystallized even if said first buried gate insulating film is heat-treated at a temperature of 700 degrees Celsius or more. ### Claim 5 (depends on 1) The semiconductor device according to claim 1, wherein said first Hf content percentage is 10 atm % to 90 atm %. ### Claim 6 (depends on 1) The semiconductor device according to claim 1, wherein said first buried gate insulating film comprises hafnium silicate. ### Claim 7 (depends on 1) The semiconductor device according to claim 1, wherein said first buried gate insulating film has a thickness ranging from 1 nm to 3.5 nm. ### Claim 8 (depends on 1) The semiconductor device according to claim 1, further comprising: a second buried gate insulating film between an inner wall of said trench of said semiconductor substrate and said first buried gate insulating film. ### Claim 9 (depends on 8) The semiconductor device according to claim 8, wherein said second buried gate insulating film comprises a silicon oxide film or a silicon oxynitride film. ### Claim 10 (depends on 1) The semiconductor device according to claim 1, wherein a part of said second transistors in said peripheral circuit region further has/have a second on-substrate gate insulating film having higher relative dielectric constant than that of silicon oxide on said first on-substrate gate insulating film. ### Claim 11 (depends on 10) The semiconductor device according to claim 10, wherein said second on-substrate gate insulating film comprises alumina. ### Claim 12 (depends on 1) The semiconductor device according to claim 1, wherein said second transistor further has a third on-substrate insulating film between said semiconductor substrate and said first on-substrate insulating film. ### Claim 13 (depends on 12) The semiconductor device according to claim 12, wherein said third on-substrate insulating film is a silicon oxide film or a silicon oxynitride film. ### Claim 14 (depends on 1) The semiconductor device according to claim 1, further comprising: a cap buried insulating film which is buried in said trench of said semiconductor substrate on said buried gate electrode. ### Claim 15 (depends on 1) The semiconductor device according to claim 1, wherein said first on-substrate gate insulating film is formed above a most upper surface of said semiconductor substrate. ### Claim 16 (depends on 1) The semiconductor device according to claim 1, wherein said first on-substrate gate insulating film comprises hafnium oxide or hafnium silicate. ### Claim 17 A semiconductor device, comprising: a first transistor and a second transistor on a semiconductor substrate; wherein said first transistor includes: a first gate insulating film which is formed along an inner wall of a trench formed in said semiconductor substrate and whose relative dielectric constant is higher than a relative dielectric constant of silicon oxide, and a first gate electrode which is buried in said trench and formed on said first gate insulating film, and comprises metal; and said second transistor includes: a second gate insulating film which is formed on a most upper surface of said semiconductor substrate and whose relative dielectric constant is higher than a relative dielectric constant of silicon oxide, and a second gate electrode which is formed on said second gate insulating film and comprises metal; said first gate insulating film and said second gate insulating film comprising a compound containing hafnium (hereinafter referred to as “hafnium-containing compound”.); wherein a first Hf content percentage, which is a content percentage of hafnium in said first gate insulating film, is different from a second Hf content percentage, which is a content percentage of hafnium in said second gate insulating film. ### Claim 18 (depends on 17) The semiconductor device according to claim 17, wherein said first Hf content percentage is lower than said second Hf content percentage. ### Claim 19 (depends on 17) The semiconductor device according to claim 17, wherein said first Hf content percentage is lower than said second Hf content percentage by 10 atm % or more. ### Claim 20 (depends on 17) The semiconductor device according to claim 17, wherein said first Hf content percentage is 10 atm % to 90 atm %.