JPH08255880A - Capacitor manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the effective area of charge storage electrode on a restricted area by a method wherein, after the formation of a polysilicon film formed of an oxide byproduct inside a contact hole, the oxide byproduct is removed to form the charge storage electrode of the porous polysilicon films. SOLUTION: After the successive formation of a field oxide film 2, a word line 4, a junction region 3, an interlayer oxide layer 5 and a bit line 6, the upper side of the whole structure is flattened by a flattening insulating film 7 to evaporate an amorphous silicon layer 8 including oxygen on a conductive layer for the charge storage electrode in the formed state of a charge storage electrode contact hole. Next, when the whole body is heat-treated, oxide byproducts 10 in SiOx form are formed between crystalline lattice among crystallized silicons 9 while crystallizing the silicon films in amorphous state. Finally, the oxide byproducts 10 are wet-removed so as to complete the charge storage electrodes 9 by the crystallized silicon only in porous polysilicon form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a capacitor of a semiconductor memory device, and more particularly, to a method of manufacturing a capacitor for increasing an effective area of a charge storage electrode of the capacitor under a limited area.

[0002]

2. Description of the Related Art Conventionally, a method of forming a capacitor is to form a field oxide film, a junction region, a word line and a bit line on a silicon substrate, then flatten the upper part of the entire structure with a flattening insulating film to form a charge storing electrode The method of contacting the junction region is used. That is, the effective area of the charge storage electrode is increased by forming a multilayer capacitor that allows the capacitor to be formed on the bit line.

[0003]

However, as semiconductor devices have become more highly integrated, it has become difficult to obtain a sufficient effective area of the charge storage electrode within the limited area according to the above conventional technique. SUMMARY OF THE INVENTION The present invention devised to solve the above-mentioned problems of the prior art aims to provide a method of manufacturing a capacitor for increasing the effective area of a charge storage electrode under a limited area. .

[0004]

In order to achieve the above object, the present invention provides a method of manufacturing a capacitor for a semiconductor device; a step of forming a charge storage electrode contact hole of the capacitor; oxygen-containing amorphous silicon. A step of depositing a film; a step of forming an oxidation byproduct while crystallizing the oxygen-containing amorphous silicon film by heat treatment; and a step of removing the oxidation byproduct, wherein the oxidation byproduct is removed. The charge storage electrode is formed of a crystallized silicon film.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 are
FIG. 1 is a cross-sectional view showing a method of forming a polysilicon film for a charge storage electrode in a contact hole according to an embodiment of the present invention. FIG. 1 shows a field oxide film (2) and a word on a silicon substrate (1). After the line (4), the junction region (3), the interlayer oxide film (5) and the bit line (6) are sequentially formed, the upper surface of the entire structure is flattened by the flattening insulating film (7), and the charge storage electrode contact hole is formed. FIG. 3 is a cross-sectional view of an amorphous silicon film (8) in which oxygen is included, which is vapor-deposited on a conductive layer for a charge storage electrode in a state in which is formed.

At this time, the deposition of the amorphous silicon film (8) containing oxygen is performed by using SiH which is a Silane gas.
₄ and N ₂ O gas are used to deposit at a low temperature of 550 ° C. to 700 ° C., and the oxygen density (Oxygen Concentration) occupies about 10% to 30% of amorphous silicon molecules.

Then, as shown in FIG. 2, when a heat treatment is performed at a temperature of 850 ° C. to 1150 ° C. for 5 hours, the amorphous silicon film is crystallized (polysiliconized) while the crystallized silicon (9) is removed. SiO ₂ or SiO x between crystal lattices
A form of oxidation by-product (10) is formed. At this time, the heat treatment is performed in an N ₂ gas atmosphere.

Finally, referring to FIG. 3, the oxidation by-product (10) is wet-removed with an HF solution to complete the charge storage electrode (9) only with the crystallized silicon (9) in the form of porous polysilicon.

[0009]

According to the present invention as described above, after forming a polysilicon film (crystallized silicon) in which an oxidation byproduct is formed inside a contact hole, the oxidation byproduct is removed to form a porous polysilicon film. The formation of the charge storage electrode has an effect of increasing the effective surface area of the charge storage electrode in a small area limited due to high integration of the device, thereby increasing the capacitance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a method of forming a polysilicon film for a charge storage electrode in a contact hole according to an embodiment of the present invention.

FIG. 2 is a sectional view of a step subsequent to that of FIG.

FIG. 3 is a sectional view of a final step.

[Explanation of symbols]

 1 Silicon Substrate 2 Field Oxide Film 3 Junction Area 4 Wordline 5 Interlayer Oxide Film 6 Bitline 7 Planarization Insulating Film 8 Amorphous Silicon Film 9 Including Oxygen 9 Crystallized Silicon

Claims (6)

[Claims] 1. A method of manufacturing a capacitor of a semiconductor device; a step of forming a charge storage electrode contact hole of a capacitor; a step of depositing an oxygen-containing amorphous silicon film; a heat treatment in which the oxygen is included. Forming an oxidation byproduct while crystallizing the amorphous silicon film; and removing the oxidation byproduct, wherein the charge storage electrode is formed of the crystallized silicon film from which the oxidation byproduct is removed. Manufacturing method of capacitor. 2. The method of manufacturing a capacitor according to claim 1, wherein the vapor deposition of the oxygen-containing amorphous silicon film uses a siren gas and an N ₂ O gas. 3. The method for manufacturing a capacitor according to claim 2, wherein the vapor deposition of the amorphous silicon film containing oxygen is performed at a low temperature of 550 ° C. to 700 ° C. 4. The method of manufacturing a capacitor according to claim 3, wherein the heat treatment is performed at a temperature of 850 ° C. to 1150 ° C. 5. The method of manufacturing a capacitor according to claim 1, wherein the oxygen density of the amorphous silicon film containing oxygen is 10% to 30%. 6. The method of manufacturing a capacitor according to claim 1, wherein the removal of the oxidation byproducts is performed by wet etching.