CN104831358B

CN104831358B - A kind of cleaning method of liquid phase epitaxy Gd-Ga garnet crystal substrate

Info

Publication number: CN104831358B
Application number: CN201510177595.2A
Authority: CN
Inventors: 杨青慧; 饶毅恒; 张怀武; 田晓洁; 范仁钰; 金曙晨; 梅兵
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2015-04-15
Filing date: 2015-04-15
Publication date: 2017-08-11
Anticipated expiration: 2035-04-15
Also published as: CN104831358A

Abstract

The invention provides a kind of cleaning method of liquid phase epitaxy with Gd-Ga garnet crystal substrate, first by the substrate successively soaking and washing in 70~80 DEG C of trichloro ethylene and deionized water respectively；Then embathed 10~15 times in the mixed liquor of 70~80 DEG C of potassium bichromate, the concentrated sulfuric acid and water, the time is embathed every time for 1~2s, soaking and washing 2 times in 70~80 DEG C of deionized water respectively after taking-up；The soaking and washing in 70~80 DEG C of alkali lye and deionized water respectively successively；The soaking and washing in weak base and deionized water respectively successively；Finally cleaned in IPA vapor.The present invention can effectively remove the impurity stain of substrate surface, make substrate that mirror effect is presented；By cleaning fluid to substrate surface slight erosion, the brilliant key of substrate base, activating surface are opened, is conducive to the attachment and growth of each film forming raw material, improves rate of film build and film quality；Using soaking and washing, it is to avoid larger substrate is due to being cleaned by ultrasonic the stress problem produced.

Description

A kind of cleaning method of liquid phase epitaxy Gd-Ga garnet crystal substrate

Technical field

The present invention relates to the cleaning method of Gd-Ga garnet substrate, and in particular to a kind of gadolinium gallium pomegranate for liquid phase epitaxy The cleaning method of stone single crystalline substrate.

Background technology

In the growth technique of film, the cleannes of substrate have vital influence to the quality of film, and surface is clear Cleanliness is poor to cause substrate surface can not film forming or the problems such as poor adhesion of thin film.It is thin that garnet is prepared in liquid phase epitaxial method During film, the surface cleanness to its conventional substrate Gd-Ga garnet (GGG) single crystalline substrate requires also very high, because liquid Phase epitaxy growth temperature is higher and growth course temperature change is larger, and the substrate of cleannes difference can have larger stress, cause Substrate fragmentation and contamination of raw material etc..Further, since being the lattice growth along substrate, substrate during rheotaxial growth film The activation degree on surface generates vital influence to the quality and performance of the film of subsequent growth.

At present, Gd-Ga garnet (GGG) single crystalline substrate is typically employed in method cleaning ultrasonic in acetone and alcohol.But It is that this method does not carry out activation process to substrate surface, is unfavorable for the growth of follow-up high-quality thin film；And for larger Substrate, the mode of ultrasonic cleaning may expand the stress inside substrate, cause substrate fragmentation.

The content of the invention

A kind of defect that the present invention exists for background technology, it is proposed that liquid phase epitaxy Gd-Ga garnet crystal substrate Cleaning method, this method, which can not only remove impurity on substrate surface, makes substrate that mirror effect is presented, can also be by cleaning fluid to lining The slight erosion of basal surface, opens the brilliant key of substrate, activating surface, is conducive to the growth of subsequent thin film.

Technical scheme is as follows：

A kind of liquid phase epitaxy cleaning method of Gd-Ga garnet crystal substrate, comprises the following steps：

Step 1：Gd-Ga garnet crystal substrate is soaked into 3~10min in 70~80 DEG C of trichloro ethylene, then 70 3~10min is soaked in~80 DEG C of deionized water；

Step 2：Substrate after step 1 is handled soaks in the mixed liquor of 70~80 DEG C of potassium bichromate, the concentrated sulfuric acid and water Wash 10~15 times, the time is embathed every time for 1~2s, wherein, the mass concentration of potassium bichromate is 18~20g/ in the mixed liquor L, the molar concentration of the concentrated sulfuric acid is 10~15mol/L；Then 2~8min is soaked in 70~80 DEG C of deionized water, after taking-up 3~10min is soaked in another 70~80 DEG C of deionized water；

Step 3：Substrate after step 2 is handled soaks 3~10min in 70~80 DEG C of alkali lye, then 70~80 DEG C deionized water in soak 3~10min；

Step 4：Substrate after step 3 is handled soaks 3~10min in weak caustic solution, then soaks in deionized water Steep 3~10min；

Step 5：Substrate after step 4 is handled cleans 3~10min in IPA vapor.

Further, alkali lye described in step 3 is sodium phosphate, sodium carbonate, the mixed aqueous solution of potassium hydroxide, the phosphoric acid The mass ratio of sodium, sodium carbonate and potassium hydroxide is 1:1:1, the mass concentration of solute is 10~15g/L in mixed liquor.

Further, weak caustic solution described in step 4 is the ammonia spirit that volumn concentration is 20~30%.

Beneficial effects of the present invention are：

1st, the cleaning method that the present invention is provided can effectively remove the impurity stain of Gd-Ga garnet crystal substrate surface, make Mirror effect is presented in substrate；By slight erosion of the cleaning fluid to substrate surface, the brilliant key of substrate base, activating surface are opened, is had Beneficial to the attachment and growth of each film forming raw material, reduce the defect and stress of interface, improve rate of film build and film quality；Using leaching The mode of bubble cleans substrate, it is to avoid larger substrate is due to being cleaned by ultrasonic the stress problem produced.

2nd, the present invention cleans substrate surface using trichloro ethylene, effectively eliminates the organic impurities of substrate surface；Then adopt Cleaned with the acid solution of potassium bichromate, corrode substrate surface passivation layer, activate substrate surface；Then cleaned in strong base solution, Neutralize surface acidity；Substrate surface acid-base property is further reduced in ammoniacal liquor, is made using the volatile characteristic soluble in water of ammoniacal liquor The close neutrality in surface；Finally by the condensing reflux of IPA vapor, again to surface degreasing decontamination, to ensure the lining after cleaning Basal surface obtains the effect of steam homogeneous film formation.

Brief description of the drawings

The cleaning method flow chart for the Gd-Ga garnet crystal substrate that Fig. 1 provides for the present invention.

Embodiment

Step 1：Gd-Ga garnet crystal substrate is soaked into 3~10min in 70~80 DEG C of trichloro ethylene, to remove base The organic impurities on piece surface, then in 70~80 DEG C of deionized water soak 3~10min remove surface trichloro ethylene and can The impurity of molten water；

Step 2：Substrate after step 1 is handled soaks in the mixed liquor of 70~80 DEG C of potassium bichromate, the concentrated sulfuric acid and water Wash 10~15 times, corrosion surface pollution passivation layer, activating surface embathe the time for 1~2s every time, wherein, in the mixed liquor The mass concentration of potassium bichromate is 18~20g/L, and the molar concentration of the concentrated sulfuric acid is 10~15mol/L；Then at 70~80 DEG C 2~8min is soaked in deionized water, 3~10min is soaked after taking-up in another 70~80 DEG C of deionized water, washes away surface Potassium bichromate and the concentrated sulfuric acid；

Step 3：It is 1 by mass ratio:1:It is 10 that 1 sodium phosphate, sodium carbonate and potassium hydroxide, which is configured to Solute mass concentration, ~15g/L mixed alkali liquor, the substrate after step 2 is handled soaks 3 in the alkali lye of 70~80 DEG C of above-mentioned preparation~ 10min, neutralizes acid, and 3~10min is then soaked in 70~80 DEG C of deionized water, aqueous slkali is washed away；

Step 4：The ammonia spirit that the volumn concentration that substrate after step 3 is handled is put at room temperature is 20~30% Middle 3~10min of soaking and washing, further removes bronsted lowry acids and bases bronsted lowry, and 3~10min is then soaked in deionized water at room temperature, removes ammonia Water；

Step 5：Substrate after step 4 is handled cleans 3~10min under the conditions of IPA vapor condensing reflux.

Embodiment

Step 1：Gd-Ga garnet crystal substrate is soaked into 5min in 80 DEG C of trichloro ethylene, to remove substrate surface Organic impurities, then soaks 5min by the substrate of taking-up in 80 DEG C of deionized water, with remove surface trichloro ethylene and can The impurity of molten water；

Step 2：Prepare the mixed liquor of potassium bichromate, the concentrated sulfuric acid and water：Precise 19.8g potassium bichromates add beaker In, then it is slowly added to be stirred continuously in the 100mL concentrated sulfuric acids, adition process into beaker, to the dissolving of most of potassium bichromate, The 100mL concentrated sulfuric acids are added, radiating is stirred continuously, stopped until adding the 660mL concentrated sulfuric acids；Then by above-mentioned potassium bichromate acid solution It is slowly added in 340mL deionized waters, is stirred continuously radiating, obtains the mixed liquor of potassium bichromate, the concentrated sulfuric acid and water；

Step 3：The mixed liquor of potassium bichromate, the concentrated sulfuric acid and water that step 2 is prepared is heated to 80 DEG C, and step 1 is cleaned The substrate obtained afterwards, which is put into the mixed liquor of above-mentioned 80 DEG C of potassium bichromate, the concentrated sulfuric acid and water, embathes 1~2s, takes out, in repetition The step 15 time embathed 1~2s, taken out is stated, to corrode substrate surface passivation layer, substrate surface is activated, embathes every time equal during taking-up Substrate is tilted, the potassium bichromate acid solution of remained on surface is removed；Then 2min is soaked in the deionized water for placing the substrate into 80 DEG C, Take out, place into another 80 DEG C clean of deionized water and soak 5min, wash away the potassium bichromate and the concentrated sulfuric acid on surface；

Step 4：Weigh 5g sodium phosphates, 5g sodium carbonate and 5g potassium hydroxide respectively to add in 1000mL deionized waters, stirring Uniformly, alkali lye is obtained；The alkali lye of preparation is heated to 80 DEG C, the substrate obtained after then step 3 is handled is put into above-mentioned 80 DEG C Alkali lye in soaking and washing 5min, take out, to neutralize acidity, then place the substrate into soaking and washing in 80 DEG C of deionized water 5min, to wash away alkali lye；

Step 5：The pure ammoniacal liquor of 285mL is added in 715mL deionized waters, is uniformly mixed, obtains ammonia spirit；Will step The substrate obtained after rapid 4 processing is put into soaking and washing 5min in the ammonia spirit of preparation, takes out, further removes sour lixiviating, then Place into and 5min is soaked in deionized water at room temperature, wash away ammonia spirit；

Step 6：Aqueous isopropanol is heated to after boiling, and the substrate obtained after step 5 is handled is placed in IPA vapor Side, 3min is cleaned by the way of IPA vapor condensing reflux to substrate, carries out degreasing decontamination to substrate surface again.

In above-mentioned cleaning process, using platinum fixture gripping substrate, it is to avoid the secondary pollution on substrate base surface.

Claims

1. a kind of liquid phase epitaxy cleaning method of Gd-Ga garnet crystal substrate, comprises the following steps：

Step 1：Gd-Ga garnet crystal substrate is soaked into 3~10min in 70~80 DEG C of trichloro ethylene, then 70~80 DEG C deionized water in soak 3~10min；

Step 2：Substrate after step 1 is handled embathes 10 in the mixed liquor of 70~80 DEG C of potassium bichromate, the concentrated sulfuric acid and water ~15 times, the time is embathed every time for 1~2s, wherein, the mass concentration of potassium bichromate is 18~20g/L in the mixed liquor, dense The molar concentration of sulfuric acid is 10~15mol/L；Then 2~8min is soaked in 70~80 DEG C of deionized water, another after taking-up 3~10min is soaked in one 70~80 DEG C of deionized water；

Step 3：Substrate after step 2 is handled soaks 3~10min in 70~80 DEG C of alkali lye, then at 70~80 DEG C 3~10min is soaked in deionized water；

Step 4：Substrate after step 3 is handled soaks 3~10min in weak caustic solution, then in deionized water immersion 3~ 10min；

Step 5：Substrate after step 4 is handled cleans 3~10min in IPA vapor.

2. the liquid phase epitaxy according to claim 1 cleaning method of Gd-Ga garnet crystal substrate, it is characterised in that step Alkali lye described in rapid 3 is sodium phosphate, sodium carbonate, the mixed aqueous solution of potassium hydroxide, the sodium phosphate, sodium carbonate and potassium hydroxide Mass ratio be 1:1:1, the mass concentration of solute is 10~15g/L in mixed liquor.

3. the liquid phase epitaxy according to claim 1 cleaning method of Gd-Ga garnet crystal substrate, it is characterised in that step Weak caustic solution described in rapid 4 is the ammonia spirit that volumn concentration is 20~30%.