# US 2014/0151688 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 2014/0151688 A1 - Document ID: US20140151688A1 - Status: Published application - Kind: A1 - Application number: 14/091,634 - Filed: 2013-11-27 - Published: 2014-06-05 - Earliest claimed: 2012-12-03 - Assignees: Semiconductor Energy Laboratory Co., Ltd. - Applicants: Semiconductor Energy Laboratory Co., Ltd. - Inventors: Shunpei YAMAZAKI - Web page: https://patentgrep.com/patent/US20140151688A1 ## CPC - H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate} - H10D 30/6704: {having supplementary regions or layers in the thin films or in the insulated bulk substrates for controlling properties of the device} - H10D 30/6715: {characterised by the doping profiles, e.g. having lightly-doped source or drain extensions} - H10D 30/6725: {having supplementary regions or layers for improving the flatness of the device} - H10D 30/6729: {characterised by the electrodes} - H10D 30/673: {characterised by the shapes, relative sizes or dispositions of the gate electrodes} - H10D 30/6757: {characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715)} - H10D 62/402: {Amorphous materials} - H10D 62/80: characterised by the materials - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract To provide a semiconductor device which can be miniaturized or highly integrated. To obtain a semiconductor device including an oxide semiconductor, which has favorable electrical characteristics. To provide a highly reliable semiconductor device including an oxide semiconductor, by suppression of a change in its electrical characteristics. The semiconductor device includes an island-like oxide semiconductor layer over an insulating surface; an insulating layer surrounding a side surface of the oxide semiconductor layer; a source electrode layer and a drain electrode layer in contact with top surfaces of the oxide semiconductor layer and the insulating layer; a gate electrode layer overlapping with the oxide semiconductor layer; and a gate insulating layer between the oxide semiconductor layer and the gate electrode layer. The source electrode layer and the drain electrode layer are provided above the top surface of the oxide semiconductor layer. The top surface of the insulating layer is planarized. ## Claims ### Claim 1 A semiconductor device comprising: an oxide semiconductor layer over an insulating surface; an insulating layer surrounding a side surface of the oxide semiconductor layer; a source electrode and a drain electrode in contact with a top surface of the insulating layer; a gate electrode overlapping with the oxide semiconductor layer; and a gate insulating layer between the oxide semiconductor layer and the gate electrode, wherein the source electrode and the drain electrode are electrically connected to the oxide semiconductor layer, and wherein the top surface of the insulating layer is planarized. ### Claim 2 (depends on 1) The semiconductor device according to claim 1, further comprising an oxide layer between the oxide semiconductor layer and the insulating layer, wherein the oxide layer is in contact with the side surface of the oxide semiconductor layer. ### Claim 3 (depends on 2) The semiconductor device according to claim 2, wherein the oxide layer comprises one or more kinds of metal elements contained in the oxide semiconductor layer. ### Claim 4 (depends on 1) The semiconductor device according to claim 1, wherein the source electrode comprises a first source electrode and a second source electrode over the first source electrode, wherein the drain electrode comprises a first drain electrode and a second drain electrode over the first drain electrode, wherein the first source electrode and the first drain electrode are in direct contact with the oxide semiconductor layer and the insulating layer, and wherein the second source electrode and the second drain electrode are in direct contact with the oxide semiconductor layer. ### Claim 5 (depends on 1) The semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises a first region having an n-type conductivity in contact with the source electrode, wherein the oxide semiconductor layer comprises a second region having an n-type conductivity in contact with the drain electrode, wherein the oxide semiconductor layer comprises a third region comprising a channel, and wherein the third region is provided between the first region and the second region. ### Claim 6 (depends on 5) The semiconductor device according to claim 5, wherein a thickness of the third region is thinner than a thickness of each of the first region and the second region. ### Claim 7 A semiconductor device comprising: an oxide semiconductor layer over an insulating surface; an insulating layer surrounding a side surface of the oxide semiconductor layer; an oxide layer between the oxide semiconductor layer and the insulating layer; a source electrode and a drain electrode in contact with a top surface of the insulating layer; a gate electrode overlapping with the oxide semiconductor layer; and a gate insulating layer between the oxide semiconductor layer and the gate electrode, wherein the source electrode and the drain electrode are electrically connected to the oxide semiconductor layer, and wherein the oxide layer is in contact with the side surface of the oxide semiconductor layer. ### Claim 8 (depends on 7) The semiconductor device according to claim 7, wherein the oxide layer comprises one or more kinds of metal elements contained in the oxide semiconductor layer. ### Claim 9 (depends on 7) The semiconductor device according to claim 7, wherein the source electrode comprises a first source electrode and a second source electrode over the first source electrode, wherein the drain electrode comprises a first drain electrode and a second drain electrode over the first drain electrode, wherein the first source electrode and the first drain electrode are in direct contact with the oxide semiconductor layer and the insulating layer, and wherein the second source electrode and the second drain electrode are in direct contact with the oxide semiconductor layer. ### Claim 10 (depends on 7) The semiconductor device according to claim 7, wherein the oxide semiconductor layer comprises a first region having an n-type conductivity in contact with the source electrode, wherein the oxide semiconductor layer comprises a second region having an n-type conductivity in contact with the drain electrode, wherein the oxide semiconductor layer comprises a third region comprising a channel, and wherein the third region is provided between the first region and the second region. ### Claim 11 (depends on 10) The semiconductor device according to claim 10, wherein a thickness of the third region is thinner than a thickness of each of the first region and the second region. ### Claim 12 A semiconductor device comprising: a first oxide layer over an insulating surface; an oxide semiconductor layer over the first oxide layer; a second oxide layer over the oxide semiconductor layer; an insulating layer surrounding a side surface of the oxide semiconductor layer; an oxide layer between the oxide semiconductor layer and the insulating layer; a source electrode and a drain electrode in contact with a top surface of the insulating layer; a gate electrode overlapping with the oxide semiconductor layer; and a gate insulating layer between the oxide semiconductor layer and the gate electrode, wherein the source electrode and the drain electrode are electrically connected to the oxide semiconductor layer, and wherein the oxide layer is in contact with the side surface of the oxide semiconductor layer. ### Claim 13 (depends on 12) The semiconductor device according to claim 12, wherein the oxide layer comprises one or more kinds of metal elements contained in the oxide semiconductor layer. ### Claim 14 (depends on 12) The semiconductor device according to claim 12, wherein the source electrode comprises a first source electrode and a second source electrode over the first source electrode, wherein the drain electrode comprises a first drain electrode and a second drain electrode over the first drain electrode, wherein the first source electrode and the first drain electrode are in direct contact with the oxide semiconductor layer and the insulating layer, and wherein the second source electrode and the second drain electrode are in direct contact with the oxide semiconductor layer. ### Claim 15 (depends on 12) The semiconductor device according to claim 12, wherein the second oxide layer is in contact with a top surface of the oxide semiconductor layer, a top surface of the source electrode, and a top surface of the drain electrode. ### Claim 16 (depends on 12) The semiconductor device according to claim 12, wherein the oxide semiconductor layer comprises a first region having an n-type conductivity in contact with the source electrode, wherein the oxide semiconductor layer comprises a second region having an n-type conductivity in contact with the drain electrode, wherein the oxide semiconductor layer comprises a third region comprising a channel, and wherein the third region is provided between the first region and the second region. ### Claim 17 (depends on 16) The semiconductor device according to claim 16, wherein a thickness of the third region is thinner than a thickness of each of the first region and the second region.