摘要:
A nitride semiconductor wafer is planar-processed by grinding a bottom surface of the wafer, etching the bottom surface by, e.g., KOH for removing a bottom process-induced degradation layer, chamfering by a rubber whetstone bonded with 100 wt %-60 wt % #3000-#600 diamond granules and 0 wt %-40 wt % oxide granules, grinding and polishing a top surface of the wafer, etching the top surface for eliminating a top process-induced degradation layer and maintaining a 0.5 μm-10 μm thick edge process-induced degradation layer.
摘要:
Provided is a test apparatus that tests a device under test, comprising a driver circuit that generates an output signal according to a prescribed input pattern, and supplies the output signal to the device under test; and a measuring section that measures a response signal output by the device under test to judge the acceptability of the device under test, wherein the driver circuit includes an input gate drive section that selects one of a plurality of input drive voltages supplied thereto, according to a logic value of the input pattern, and outputs the selected input drive voltage; a voltage switching section that includes a transistor and that outputs the output signal according to the drain voltage of the transistor, the transistor having a gate terminal that receives the input drive voltage output by the input gate drive section and a source terminal to which is applied a prescribed reference voltage; and an input drive voltage supplying section that generates the input drive voltages according to the reference voltage, and supplies the input drive voltages to the input gate drive section.
摘要:
Nitride semiconductor wafers which are produced by epitaxially grown nitride films on a foreign undersubstrate in vapor phase have strong inner stress due to misfit between the nitride and the undersubstrate material. A GaN wafer which has made by piling GaN films upon a GaAs undersubstrate in vapor phase and eliminating the GaAs undersubstrate bends upward due to the inner stress owing to the misfit of lattice constants between GaN and GaAs.
摘要:
A method of producing a GaN crystal is directed to growing a GaN crystal on a GaN seed crystal substrate. The method includes the steps of preparing a GaN seed crystal substrate including a first dopant such that the thermal expansion coefficient of the GaN seed crystal substrate becomes greater than that of the GaN crystal, and growing the GaN crystal to a thickness of at least 1 mm on the GaN seed crystal substrate. Accordingly, there can be provided a method of producing a GaN crystal that can suppress generation of a crack and grow a thick GaN crystal, and a GaN crystal substrate.
摘要:
A driver circuit includes a main driver which receives an input signal and outputs a first signal corresponding to the input signal, a sub driver which receives the input signal and outputs a non-inverted signal and an inverted signal corresponding to the input signal, a differentiating circuit including resistors and a variable capacity condenser, which outputs signals by differentiating the non-inverted signal and the inverted signal, respectively, and an addition unit which outputs a high frequency emphasized signal given by adding the output signal of the main driver and the signal given by differentiating the non-inverted signal, or a low frequency emphasized signal given by adding the output signal of the main driver and the signal given by differentiating the inverted signal.
摘要:
A method for surface treatment of a group III nitride crystal includes the steps of lapping a surface of a group III nitride crystal using a hard abrasive grain with a Mohs hardness higher than 7, and abrasive-grain-free polishing the lapped surface of the group III nitride crystal using a polishing solution without containing abrasive grain, and the polishing solution without containing abrasive grain has a pH of not less than 1 and not more than 6, or not less than 8.5 and not more than 14. Accordingly, the method for surface treatment of a group III nitride crystal can be provided according to which hard abrasive grains remaining at the lapped crystal can be removed to reduce impurities at the crystal surface.
摘要:
A surface wave plasma (SWP) source having an electromagnetic (EM) wave launcher configured to couple EM energy in a desired EM wave mode to a plasma by generating a surface wave on a plasma surface of the EM wave launcher adjacent the plasma. A power coupling system is coupled to the EM wave launcher, and configured to provide the EM energy to the EM wave launcher for forming the plasma. A mode scrambler coupled to the plasma surface of the EM wave launcher, and configured to reduce mode jumping between the desired EM wave mode and another EM wave mode.
摘要:
A novel material having high hole-transporting ability and a high glass transition temperature and having long-lasting durability is obtained.A benzofluorene compound represented by formula (1) is used. (In the formula, M is a substituted or unsubstituted aryl group having 6-40 carbon atoms or a substituted or unsubstituted heteroaryl group having 5-40 carbon atoms; Ar1 to Ar4 each independently is a substituted or unsubstituted aryl group having 6-40 carbon atoms or a substituted or unsubstituted heteroaryl group having 5-40 carbon atoms, provided that at least one of Ar1 to Ar4 is a substituent represented by any of the following formulae (2) to (5); and p is an integer of 0-2.) (In the formulae, R1 to R4 each independently is a hydrogen atom, a halogen atom, a substituted or unsubstituted amino group, a linear, branched, or cyclic alkyl group, a linear, branched, or cyclic alkoxy group, a substituted or unsubstituted aryl group having 6-40 carbon atoms, or a substituted or unsubstituted aryloxy group having 6-40 carbon atoms, provided that R1 and R2 may be bonded to each other to form a ring.)
摘要:
A test apparatus for testing a device under test is provided. The test apparatus includes a test signal generating section for generating a test signal to be provided to the device under test, a driver circuit for providing the test signal to the device under test and a determination section for determining whether is good or bad of the device under test based on the output signal outputted by the device under test according to the test signal. The driver circuit includes a main driver and a sub-driver for outputting drive signals according to the test signal, respectively, a differentiating circuit for outputting a differentiated signal obtained by differentiating the drive signal outputted by the sub-driver and an adding section for providing a signal having the waveform according to the test signal which is obtained by adding the differentiated signal to the drive signal outputted by the main driver to the device under test.
摘要:
An ingot 3 of a hexagonal III-nitride crystal is cut using a wire array 21 composed of a wire 22. On this occasion, the ingot 3 is cut in such a manner that the ingot 3 is sliced with supply of an abrasive fluid while feeding at least one of the ingot 3 and wire 22 in a direction perpendicular to an extending direction B of the wire 22. During cutting the ingot 3, the extending direction B of the wire 22 is inclined at 3° or more to the {1-100} plane of the ingot 3.