SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20140175433A1
• Filed: 12/19/2013
• Published: 06/26/2014
• Est. Priority Date: 12/25/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei, MIYAKE, Hiroyuki
• Granted Patent: US 9,905,585 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 27/1259 Multistep manufacturing methods

Abstract

A semiconductor device in which the aperture ratio and which includes a capacitor with increased charge capacity is provided. A semiconductor device in which the number of masks used in a manufacturing process is reduced and the manufacturing costs are reduced is also provided. An impurity is contained in a light-transmitting semiconductor film so that the semiconductor film functions as one of a pair of electrodes in a capacitor. The other pair of electrodes is formed using a light-transmitting conductive film such as a pixel electrode. Further, a scan line and a capacitor line are provided on the same surface and in parallel to each other. An opening reaching the capacitor line and an opening reaching a conductive film which can be formed in the formation of a source electrode or a drain electrode of the transistor can be formed concurrently in an insulating film.

Claims

1. A semiconductor device comprising:

a transistor comprising a gate electrode, a source electrode, a drain electrode, and a light-transmitting semiconductor film;

a light-transmitting conductive film on a surface where the light-transmitting semiconductor film is formed, wherein the light-transmitting conductive film functions as one of a pair of electrodes of a capacitor;

an insulating film over the light-transmitting conductive film, wherein the insulating film functions as a dielectric film of the capacitor,

a pixel electrode electrically connected to the transistor, wherein the pixel electrode functions as the other of the pair of electrodes of the capacitor;

a capacitor line on a surface where the gate electrode is formed;

an electrode on a surface where the pixel electrode is formed; and

a conductive film on a surface where the source electrode or the drain electrode is formed,

wherein the capacitor line is electrically connected to the light-transmitting conductive film through the electrode and the conductive film, and

wherein the light-transmitting conductive film includes a region whose conductivity is higher than the conductivity of the light-transmitting semiconductor film.

2. The semiconductor device according to claim 1,

wherein the light-transmitting semiconductor film is over the gate electrode,

wherein the source electrode and the drain electrode are over the light-transmitting semiconductor film, and

wherein the electrode is over the conductive film.

3. The semiconductor device according to claim 1,

wherein the light-transmitting semiconductor film is an oxide semiconductor film.

4. The semiconductor device according to claim 3, further comprising a first oxide film and a second oxide film between which the oxide semiconductor film is interposed.

5. The semiconductor device according to claim 1,

wherein the light-transmitting conductive film comprises one or more elements selected from the group consisting of hydrogen, boron, nitrogen, fluorine, aluminum, phosphorus, arsenic, indium, tin, antimony, and a rare gas element.

6. A semiconductor device comprising:

a transistor comprising a gate electrode, a source electrode, a drain electrode, and a light-transmitting semiconductor film;

an insulating film having a stacked structure of an oxide insulating film and a nitride insulating film over the oxide insulating film, wherein the insulating film is over the light-transmitting semiconductor film;

a light-transmitting conductive film on a surface where the light-transmitting semiconductor film is formed, wherein the light-transmitting conductive film is in contact with the nitride insulating film and functions as one of a pair of electrodes of a capacitor;

a pixel electrode electrically connected to the transistor, wherein the pixel electrode functions as the other of the pair of electrodes of the capacitor;

a capacitor line on a surface where the gate electrode is formed;

an electrode on a surface where the pixel electrode is formed; and

a conductive film on a surface where the source electrode or the drain electrode is formed,

wherein the nitride insulating film functions as a dielectric film of the capacitor,

wherein the capacitor line is electrically connected to the light-transmitting conductive film through the electrode and the conductive film, and

wherein the light-transmitting conductive film includes a region whose conductivity is higher than the conductivity of the light-transmitting semiconductor film.

7. The semiconductor device according to claim 6,

wherein the light-transmitting semiconductor film is over the gate electrode,

wherein the source electrode and the drain electrode are over the light transmitting semiconductor film, and

wherein the electrode is over the conductive film.

8. The semiconductor device according to claim 6,

wherein the light-transmitting semiconductor film is an oxide semiconductor film.

9. The semiconductor device according to claim 8, further comprising a first oxide film and a second oxide film between which the oxide semiconductor film is interposed.

10. The semiconductor device according to claim 6,

wherein the light-transmitting conductive film comprises one or more elements selected from the group consisting of hydrogen, boron, nitrogen, fluorine, aluminum, phosphorus, arsenic, indium, tin, antimony, and a rare gas element.

11. A method for manufacturing a semiconductor device comprising a transistor and a capacitor, comprising the steps of:

forming a gate electrode of the transistor and a capacitor line;

forming a first insulating film over the gate electrode and the capacitor line;

forming, over the first insulating film, a light-transmitting semiconductor film of the transistor and a light-transmitting semiconductor film functioning as one of a pair of electrodes of the capacitor;

doping the light-transmitting semiconductor film of the capacitor with a dopant to form a light-transmitting conductive film;

forming a source electrode and a drain electrode over the first insulating film and the light-transmitting semiconductor film of the transistor and forming a conductive film over the first insulating film and the light-transmitting conductive film of the capacitor;

forming a second insulating film over the first insulating film, the source electrode, the drain electrode, and the conductive film;

forming a first opening reaching the capacitor line in the first insulating film and the second insulating film and forming a second opening reaching the conductive film in the second insulating film concurrently; and

forming an electrode over the second insulating film and in the first opening and the second opening and forming a pixel electrode overlapping with the light-transmitting conductive film of the capacitor and functioning as the other of the pair of electrodes of the capacitor.

12. The method for manufacturing a semiconductor device, according to claim 11,

wherein the second insulating film has a stacked structure of an oxide insulating film and a nitride insulating film over the oxide insulating film.

13. A method for manufacturing a semiconductor device comprising a transistor and a capacitor, comprising the steps of:

forming a gate electrode of the transistor and a capacitor line;

forming a first insulating film over the gate electrode and the capacitor line;

forming, over the first insulating film, a light-transmitting semiconductor film of the transistor and a light-transmitting semiconductor film functioning as one of a pair of electrodes of the capacitor;

forming a source electrode and a drain electrode over the first insulating film and the light-transmitting semiconductor film of the transistor and forming a conductive film over the first insulating film and the light-transmitting semiconductor film of the capacitor;

forming a second insulating film over the first insulating film, the source electrode, the drain electrode, and the conductive film;

processing part of the second insulating film to expose the light-transmitting semiconductor film of the capacitor;

forming a third insulating film over the second insulating film and the exposed light-transmitting semiconductor film of the capacitor;

forming a light-transmitting conductive film by dispersion of a component of the third insulating film into the light-transmitting semiconductor film of the capacitor;

forming a first opening reaching the capacitor line in the first insulating film, the second insulating film, and the third insulating film and forming a second opening reaching the conductive film in the second insulating film and the third insulating film concurrently; and

forming an electrode over the second insulating film and in the first opening and the second opening and forming a pixel electrode overlapping with the light-transmitting conductive film of the capacitor and functioning as the other of the pair of electrodes of the capacitor.

14. The method for manufacturing a semiconductor device, according to claim 13,

wherein the second insulating film includes an oxide insulating film and the third insulating film includes a nitride insulating film.