Reflection liquid crystal display and a semiconductor device for the display

• US 5,990,988 A
• Filed: 08/30/1996
• Issued: 11/23/1999
• Est. Priority Date: 09/01/1995
• Status: Expired due to Fees

• Current Assignee: Pioneer Micro Technology Corporation (Pioneer Corporation)
• Original Assignee: Pioneer Electronics Corporation (Pioneer Corporation), Pioneer Video Corporation (Pioneer Corporation)
• Inventors: Hanihara, Koji, Ohkuni, Motohisa, Ishii, Kunihisa, Hanada, Kenichi, Tsuchiya, Itaru
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US08/697,867
• Time in Patent Office: 1,180 Days
• Field of Search: 349/42, 349/110, 349/43, 349/111, 349/48, 349/122, 349/139, 349/147, 349/113, 349/114, 257/72, 257/351, 257/369, 345/92, 345/93
• US Class Current: 349/48
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136245 having complementary transistors
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon

Abstract

A liquid crystal display device has a semiconductor substrate. A plurality of switching elements are arranged on the substrate in matrix, and a plurality of pixel electrodes are provided above the switching elements, arranged in matrix corresponding to the switching elements. A liquid crystal layer is provided on the pixel electrodes. The switching element is connected with a corresponding pixel electrode by a wiring layer. Dummy layers are provided in the same level as the wiring layer so that a surface of the dummy layer is substantially flush with a surface of the wiring layer.

Claims

1. A reflection liquid crystal display device having a semiconductor substrate, comprising:

a plurality of switching elements arranged on the semiconductor substrate in a matrix;

a plurality of pixel electrodes above the plurality of switching elements and arranged in a matrix corresponding to the plurality of switching elements;

a unit of wiring layers connecting a unit of the plurality of switching elements with each other and connecting the unit of the plurality of switching elements with a corresponding pixel electrode;

a liquid crystal layer on the plurality of pixel electrodes; and

a unit of dummy layers in a same level as the unit of wiring layers so that an uppermost surface of the unit of dummy layers is substantially flush with an uppermost surface of the unit of wiring layers, the unit of dummy layers forming a storage capacitor together with the corresponding pixel electrode.

2. The device according to claim 1, wherein surfaces of the plurality of pixel electrodes on a side of the liquid crystal layer are ground substantially flat.

3. The device according to claim 1, further comprising a protection layer having a ground flat surface on the plurality of pixel electrodes.

4. The device according to claim 3, further comprising a dielectric mirror on the protection layer.

5. A reflection liquid crystal display device having a semiconductor substrate, comprising:

a plurality of switching elements arranged on the semiconductor substrate in a matrix;

a plurality of pixel electrodes above the plurality of switching elements and arranged in a matrix corresponding to the plurality of switching elements;

a unit of wiring layers connecting a unit of the plurality of switching elements with each other and also connecting the unit of the plurality of switching elements with a corresponding pixel electrode, the unit of wiring layers further including a dummy layer having an upper surface flush with an upper surface of the unit of wiring layers and forming a storage capacitor with a corresponding pixel electrode;

a liquid crystal layer on the plurality of pixel electrodes; and

a p-channel MOSFET and an n-channel MOSFET connected to form a transfer gate for the corresponding pixel electrode and forming the unit of the plurality of switching elements.

6. A liquid crystal display device comprising:

a first switching element of a first conductivity type on a semiconductor substrate;

a second switching element of a second conductivity type on the semiconductor substrate;

a pixel electrode disposed over the first and second switching element;

a wiring layer for connecting the first switching element to the second switching element and for connecting the first and second switching elements to the pixel electrode, the wiring layer including a dummy layer having an upper surface flush with an upper surface of the wiring layer, the dummy layer forming a storage capacitor together with the pixel electrode; and

a liquid crystal layer disposed over the pixel electrode.

7. The liquid crystal display device of claim 6, wherein the first switching element of the first conductivity type is a p-channel MOSFET.

8. The liquid crystal display device of claim 7, wherein the second switching element of the second conductivity type is an n-channel MOSFET.

9. The liquid crystal display device of claim 8, wherein the p-channel MOSFET includes a source and a drain each having a lightly doped region and a heavily doped region, and

wherein the n-channel MOSFET includes a source and a drain each having a lightly doped region and a heavily doped region.

10. The liquid crystal display device of claim 9, wherein an edge of a p-layer formed under a field oxidation film of the p-channel MOSFET is offset from the lightly doped regions of the source and the drain of the n-channel MOSFET.

11. The liquid crystal display device of claim 6, further including a protection layer on the pixel electrode.

12. The liquid crystal display device of claim 11, further including a dielectric mirror on the protection layer.

13. The liquid crystal display device of claim 6, further including an alignment film over the liquid crystal layer.

14. The liquid crystal display device of claim 13, further including a transparent electrode over the alignment film.

15. The liquid crystal display device of claim 6, wherein an upper surface of the pixel electrode is ground substantially flat.

16. The liquid crystal display device of claim 14, further including a glass layer over the transparent electrode.