METHOD FOR REMOVING PROCESSING DEFECT OF GALLIUM NITRIDE SUBSTRATE

Hereinafter with reference to the attached drawing of the present invention in the embodiment are detailed as follows. In describing the present invention, publicly known related function or configuration description is the subject matter of invention specifically breach can be decided to omit description if the analogy will. In addition, the specification of the present invention preferred embodiment used in the properly as terms used in the order terms, this user, by means of which said operator and flawless depending on intended or the present invention such as can be. Thus, the terms for definition throughout the content based on the specification will been commanded. Each drawing number [...] exhibits the same member to the same references.

The entire specification, that the "on" position when any member other members, as well as any other elements member between the two members when joined to another member to if there is a comprises a unit.

The entire specification, that "comprising" when any portion of any components, particularly the opposite substrate [...] number but without other components further can include other components which means that the other.

Hereinafter, with reference to the drawing and in the embodiment of the present invention method for wetting ability of GaN substrate processing deficiency number illustrating specifically to each other. However, the present invention is the use of this in the embodiment and drawing number to one and not.

In the embodiment of the present invention according to one, said gallium nitride substrate chemically etched GaN single crystal substrate formed on the surface of a portion of the machining industry deficiency number 1 difference etching step; and said portion of the gallium nitride substrate for reparing over said whole number physically etching processing deficiency deficiency number 2 difference etching processing industry; including a, a number of GaN substrate processing method being resized deficiency number [...] substrate.

Nitrification gallium growth and is general method (grinding (grinding) process, lapping (lapping) process, polishing (polishing) process) processed using gallium nitride surface fabricating deficiency which is provided to the user, in the embodiment of the present invention in one, process industry a number of GaN substrate remaining after such processing deficiency are disclosed.

In the embodiment according to the method of the present invention one deficiency number processing of GaN substrate wetting ability, chemically etched in a GaN single crystal substrate 1 difference after smooth GaN single crystal substrate surface by at least one of physically 2 difference can be achieved. 2 gallium nitride of high quality by performing chemical and physical fabrication has the interior surface, can mask, light-emitting element number excellent properties can be high pressure liquid coolant.

In the embodiment according to Figure 3 shows a GaN single crystal substrate of the present invention also a coarse method would also 1 to visually representing a cross-section process one deficiency number processing are disclosed.

The reference also 1, chemically formed on the surface of said GaN single crystal substrate 1 by selectively etching a portion of the gallium nitride substrate machining deficiency number other stand-alone.

In one, the gallium nitride substrate, nitrification gallium homo grown on gallium nitride substrate or substrate, sapphire (Al₂ O₃ ), Silicon carbide (SiC), silicon (Si) on a substrate such as a hydrogen firearm-phase epitaxy method (Hydride Vapor Phase Epitaxial; HVPE), metalorganic chemical vapor deposition method (metal organic chemical vapor depositioon; MOCVD), molecular beam epitaxy (molecular beam epitaxy; MBE) method, sublimation (sublimation) gallium nitride (GaN) like method and bulk crystal growth (bulk crystal growth) by using a thick film can be used.

In one, the processing on the surface of the gallium nitride substrate deficiency, as well as a projecting part out relief as protrusion, a plurality of protrusions can be depressed portion is indented on the protrusion.

In one side, said 1 in a second etching step, an inductively coupled plasma (inductively coupled plasma; ICP), optical - reinforced formula each (photo-a enhanced chemical etching), reactive ion etching (reactive ion etching; RIE), magnetic - enhanced reactive ion etching (magnetic enhanced reactive ion etching; MERIE), - inductively coupled plasma reactive ion etching (ICP-a RIE) and method for wet etching is performed by a method selected from the group consisting of at least one be a.

For example, an inductively coupled plasma (ICP) etching using high density plasma process using RF power is provided by the engagement of a condenser 10 inductively plasma¹¹ /Cm3 or more capable of etching an etch plasma density and high weight percent over the causes. For example, bromine (HBr) or hydrogen chloride (BCl₃ ) 1 cc to 200 cc per minute a layer is formed on the flow rate of fluid, 50 W to 100 W high frequency power, DC bias of 100 V to 300 V 1 mmTorr to 10 mmTorr pressure similar to that carried out in the to be a 100 °C.

For example, reactive ion etching (RIE) etching plasma ion by means of reaction with are disclosed.

For example, the optical - enhanced chemical etching (photo-a enhanced chemical etching), electrolyte solution (M) after charging the main sky light mask layer dielectric layer for reparing over the number are disclosed.

For example, exposure of the magnetic field (magnetic enhanced reactive ion etching; MERIE) - enhanced reactive ion etching magnetic applied using etching process are disclosed.

For example, wet etching or machining deficiency by exposing industry to control an opening degree number are disclosed. In a process of etching solution used for etching a number deficiency a stand-alone solution are disclosed. Machining deficiency along said etching solution to penetrate preferentially etching processing deficiency can be disclosed. The HF etching solution, HCl, KOH, NH₄ OH H₃ PO₄ , H₂ SO₄ , NaOH, H₂ O₂ And K₂ S₂ O₈ Selected from the group consisting of including at least either a may be disclosed. Wet etching is a wet etching solution for wet etching method capable of penetrating and acting to hereinafter worked deficiency can be installed symmetrically to shorten the time required for etching solution can be by exposure of the channel layer.

In one side, said short time difference etching chemical 1 can be performed. For example, when performed using inductively coupled plasma, a large ion energy emitted by deficiency in the terminal as well as gallium nitride substrate processing on gallium nitride surfaces may have, in gallium nitride substrate is introduced into a current component increases with suspended in the ion recombination can be turned into high disclosed. Chemically etching part 1 deficiency for long periods of time can be concentrated short time difference self etching the dielectric etch processing deficiency portion in which the number can be a billion.

In one side, said chemical etching step 1 difference decoding few seconds, e.g., 30 seconds to 20 minutes, preferably, 1 to about 5 minutes of short time can be performed. 1 difference etching few seconds when performed during decoding, processing deficiency on gallium nitride substrate by etching physically 2 difference when a stand-alone some number, than flat mirror (mirror) surface can be inducing etching can be implemented. The, chemical 1 difference etching step performed a short time only a portion can be a stand-alone the number by a machining deficiency.

In one side, a portion of said processing deficiency industry association step number, said protruding portions and the depressed part is a 40% to 60% number during processing deficiency carried out until be a hypoglycemic agent. A number of protruding portions and the depressed part is a 60% said processing deficiency in excess when the protruding portions and the depressed part is a hypoglycemic agent is too depth when at least one of gallium nitride surfaces physically 2 difference in the terminal flow tides. During protruding portions and the depressed part is a less than 40% when said processing deficiency 2 deficiency even when the surface of a gallium nitride is deposited later physical difference number not be completely wetting ability.

In one side, said processing deficiency deficiency can be preferentially number during processing at the top surface and the wetting ability, a projecting part and a protruding part of the longer between first deep recessed is indented on the billion number be a heavy load.

Although not shown in the drawing, chemical 1 difference carried out before etching, physical 2 difference etching step carried out before preparation of gallium nitride substrate can be further washed. Between each step through ultrasonic contaminants that may be adsorbed on the gallium nitride substrate alone without affecting the previous step can be to what's the next number.

The reference 2 also, a portion of the gallium nitride substrate for reparing over etch processing deficiency number via a physical 2 difference entire gallium nitride substrate processing deficiency number other stand-alone. Performing said step surface of said chemical 1 difference [...] deficiency only impossible to completely number 2 is a stand-alone physical etch step difference can be performed.

In one side, said 2 6 in a second etching step. 00E-a 04 torr to 8. 00E-a 04 torr base pressure, 6. 00E-a 02 torr to 7. 00E-a 02 torr gas pressure, at a temperature ranging from -10 °C to 10 °C, 120 V to 130 V of DC power, 630 V to 660 V voltage, 20 A to 50 A carried out in an inert gas be a current conditions.

In one side, said 2 difference chemically etching unreacted gas can be physical etching pattern as a mask. Physical etching using a fluorine containing gas with an inert gas or inert gas as be a. Said inert gas is, e.g., Ar, He, Ne, Kr, Xe and F at least one element selected from the group consisting of cost be a. Said F-based etching gas includes, SF-based gas using CF sequence and can be either.

In one side, said 2 difference etching step can be different from that of the higher depending on time. A packet processing on said 2 difference etching time too short stand-alone may not be completely number gallium nitride substrate deficiency and, on the basis of importance and vice versa when said 2 protection due to gallium nitride surfaces of etched can be applied. The, step of time may door without causing said physical 2 difference number point within a range that can be perform according to the etching conditions.

In one side, said 2 difference between first raised portion and a protruding part of the etch is indented on the recessed surface of the gallium nitride coating while minimizing progression of the deficiency can be a stand-alone number precisely flatness by processing whole number.

The reference also 3, 1 2 2 chemical and physical etching step difference of importance and performing photolithography process number for reparing over the entire processing deficiency presents a gallium nitride substrate. Flat mirror (mirror) surface can be implementing.

In one side, the second metal layer has a surface roughness (RMS) of GaN substrate after said 2 0. Less than 15 nm can be. [...] surface roughness measured results through atomic force microscope (atomic force microscopy; AFM) be a.

In one side, said 2 difference after etching the dislocation density GaN single crystal substrate 5. 0 × 10⁵ /Cm² To 1. 0 × 10⁷ /Cm² Can be one having an. Phase epitaxy (HVPE) growth method and is typically a hydrogen firearm general method to nitrification gallium (grinding (grinding) process polishing (polishing) process→wrapping (lapping) process→) processed using gallium nitride surface fabricating deficiency which is provided to the user, the present invention according to chemical and physical etching step of etching step 2 2 1 difference difference by performing fabrication, in the machining process can be effectively significantly reduces the deficiency, and an optical element formed thereon of chalcogenide element performance can be markedly improves the

Single crystal gallium nitride substrate of the present invention observed dark spot (dark spot) to one in the embodiment according to difference in chemical and physical etching step of etching step 2 1 2 difference fabrication can be also dark spot is observed even performing GaN single crystal substrate.

The present invention refers to chemical 1 difference step performed during a short time and, in a short time the physical 2 difference etching step performed during the GaN single crystal substrate by performing an etch reactor chamber 2 deficiency may have an even surface for reparing over the number. The, surface roughness is equal to or higher have flat.

Hereinafter, embodiments of the present invention to in the embodiment and comparison to explain with reference to passing of less than 1000. However, technical idea of the present invention wherein number by one or limited endured.

[In the embodiment]

- An inductively coupled plasma reactive ion etching (ICP-a RIE) gallium nitride substrate utilizing a mobile device, base pressure 7. In 00E provided 7 torr, Ar 11 sccm and Cl₂ 20 sccm while into, the top power of 400 W, 400 W of power, 5 mTorr pressure difference 60 seconds 1 conducting chemical etch. 2 base pressure difference 6. 00E-a 04 torr Ar gas in 6. 40E-a 02 torr -7 °C gas pressure at a temperature of, 2 cm distance, DC power 124 V, 651 V voltage, current 34 mA 15 minutes in physical thickness 1,000 Å is deposited by etching the surface of GaN substrate processing deficiency number been stand-alone a gallium nitride substrate.

[Comparison example]

Relate a gallium nitride substrate grinding process, lapping process, polishing process using the process of conducting.

Figure 4 atomic force microscope (AFM) Image surface finish of the surface of the gallium nitride substrate are disclosed. The reference also 4, the surface of the gallium nitride substrate surface roughness (RMS) surface finish is 0. 47 nm shown to scratch such as a buckle can be shown in an deficiency to know.

Figure 5 surface finish GaN substrate surface of cathode ray light emitting (CL) Image are disclosed. The reference also 5, dark spot (dark spot) is observed due to the front surface of the gallium nitride substrate layer does not.

Figure 6 according to an embodiment of the present invention 2 atomic force microscope (AFM) Image of the surface of the etched GaN substrate steps are disclosed. 6 also reference surface, according to an embodiment of the present invention the surface of the gallium nitride substrate surface roughness (RMS) is 0. As shown by the 147 nm has a uniform crystal plane having a processing deficiency can be confirmed.

Figure 7 according to an embodiment of the present invention 2 etched GaN substrate surface of cathode ray light emitting step (CL) Image are disclosed. The reference also 7, is provided to convert single crystal gallium nitride substrate according to an embodiment of the present invention observed in gallium nitride substrate dark spot (dark spot) can be observing high degree of crystallization can be predetermined position of gallium nitride substrate. The dislocation density 4. 2 × 10⁶ Cm² A grating constant difference is caused by the dislocation density is low can be confirmed.

Atomic force microscope (AFM) Image of the surface of the gallium nitride substrate according to comparison example Figure 8 of the present invention are disclosed. 8 also reference surface, surface roughness (RMS) of the present invention the surface of the gallium nitride substrate according to comparison example is 0. As shown in eye surface state is not know to artificial pearl 97 nm can be installed.

Although the present invention refers to than in the embodiment described by the defined on the drawing but, in the embodiment of the present invention refers to said limited to has the, from the substrate in the present invention if the person with skill in the art various modifications and flawless deformable disclosed. Thus, in the embodiment of the present invention is not described does not require any limited in range, as well as the carry evenly defined by claim claim on others should.