Patent ID: 8476086

Claim:
A method of manufacturing a plurality of semiconductor devices, each of device principal-face surface area S c predetermined by an at least 1 mm 2 minimum size allowing the device to be functional, on a GaN device wafer screened from a plurality of vapor-phase grown GaN substrates to ensure a minimum 10% yield from the plurality of semiconductor devices, as defined by a minimum reverse breakdown voltage acceptable for the devices to be products, the method comprising: a step of producing a plurality of GaN substrates by an inversion-domain reducing vapor-phase growth process, the substrates each defining a principal face that is either the (0001) Ga face or a surface vicinally misoriented with respect to the (0001) Ga face; a step of testing the plurality of GaN substrates to screen for a minimum 10% device yield, said testing and screening step including a substep of characterizing inversion domains in the principal face of each of the plurality of GaN substrates by one technique selected from i) etching the substrates with a predetermined alkali solution for a predetermined time at a predetermined temperature, ii) cathodoluminescence, or iii) observation under a fluorescence microscope, and based on the inversion-domain characterization, determining, for each of the plurality of GaN substrates, the principal-face area S t cm 2 of the inversion domains collectively, finding the ratio S t / S, of S t to the total area S cm 2 of the substrate principal face, and selecting, as prepared GaN substrates from the plurality of GaN substrates, GaN substrates whose S t /S is not greater than 0.5; a substep of determining the number of inversion domains of 1 μm 2 or greater surface area in the principal face of the prepared GaN substrates, as D cm −2 ; and a substep of selecting those prepared GaN substrates whose product S c ×D is less than 2.3, as correlating to a device yield of at least 10% from semiconductor devices, each of said principal-face functional surface area S c when grown on the substrates; a step of growing an at least single-lamina, device-forming semiconductor layer onto the principal face of the selected prepared GaN substrates; a step of dividing each of the selected prepared GaN substrates, on which the device-forming semiconductor layer has been grown into chips each of area S c ; a step of reverse-breakdown-voltage testing the device chips for the at least 10% whose reverse breakdown voltage is at or above the acceptable minimum.