DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of the Claims
Applicant’s election without traverse of Group I and Species 2, as shown in FIG. 3, in the reply filed on March 30, 2026 is acknowledged. Applicant identifies claims 1-6 are readable on the Elected Group I, and Species 2.
Non-elected Inventions and/or Species, claims 7-21 have been withdrawn from consideration. Claims 1-21 are pending.
Action on merits of the Elected Invention and Species, claims 1-6 follows.
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on February 28, 2023 and July 30, 2025 have been considered by the examiner.
Specification
The lengthy specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification.
The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed.
The following title is suggested:
VDMOS SILICON CARBIDE SEMICONDUCTOR DEVICE WITH PARALLEL PN LAYER UNDER DEVICE STRUCTURES HAVING AMOUNT OF A SECOND-CONDUCTIVITY-TYPE CHARGE DECREASING FROM TOP SURFACE TO BOTTOM SURFACE
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-6 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by SAITO et al. (US. Patent No. 6,888,195).
With respect to claim 1, SAITO teaches a silicon carbide semiconductor device, as claimed including:
a semiconductor substrate containing silicon carbide, the semiconductor substrate having a first main surface (Top, T) and a second main surface (Bottom, B) that are opposite to each other;
a parallel pn layer (3/4) provided in the semiconductor substrate, the parallel pn layer (3/4) having therein a plurality of first-conductivity-type regions (3) and a plurality of second-conductivity-type regions (4) disposed adjacent to one another so as to repeatedly alternate with one another in a direction that is parallel to the first main surface (T) of the semiconductor substrate;
a device structure provided between the first main surface (T) and the parallel pn layer (3/4);
a first electrode (7) provided on the first main surface (T) and electrically connected to the device structure; and
a second electrode (1) provided on the second main surface (B) of the semiconductor substrate, wherein
the parallel pn layer (3/4) has a standard portion (Middle, M), a first portion (1) and a second portion (2), the standard portion (M) being located at a standard depth that is a center of the parallel pn layer (3/4) in a depth direction (Z) or having a range of depth, a center of the range of depth being located at the standard depth, the first portion (1) being located closer to the first main surface (T) than is the standard portion (M), the second portion (2) being located closer to the second main surface (B) than is the standard portion (M),
between each adjacent two regions that includes one first-conductivity-type region (3) and one second-conductivity-type region (4) of the parallel pn layer (3/4) that are adjacent to each other,
in the standard portion (M), an amount of a first-conductivity-type charge (QNM) and an amount of a second-conductivity-type charge (QPM) meet a standard condition,
in the first portion (1), an amount of the second-conductivity-type charge (QP1)
is greater than (>) an amount of the first-conductivity-type charge (QN1),
is greater than (>) an (sic) amount of the second-conductivity-type charge (QPM) in the standard portion, and
continuously increases with a first gradient in a first direction (up) that is the depth direction from the standard portion (M) toward the first main surface (T),
in the second portion (2),
an amount of the first-conductivity-type charge (QN2) is greater than (>) the amount of the second-conductivity-type charge (QP2),
an amount of the second-conductivity-type charge (QP2)
is less than (<) the amount of the second-conductivity-type charge (QPM) of the standard portion (M), and
continuously decreases with a second gradient in a second direction (down) that is the depth direction from the standard portion (M) toward the second main surface (B). (See FIGs. 1A-B).
With respect to claim 2, an absolute value of the first gradient of SAITO is greater than an absolute value of the second gradient.
With respect to claim 3, an equation “CB=(Qp-Qn/Qn)×100” is satisfied in the parallel pn layer (3/4), where, “Qp=Na×Wp” and “Qn=Nd×Wn”, “Na” and “Wp” respectively represent a carrier concentration and a width of the one first-conductivity-type region included in said each adjacent two regions, and “Nd” and “Wn” respectively represent a carrier concentration and a width of the one second-conductivity-type region included in said each adjacent two regions, the CB has an upper limit of +160% in the first portion and a lower limit of -30% in the second portion.
With respect to claim 4, an equation “CB=(Qp-Qn/Qn)×100” and an expression “5≤
|
CB1+/CB1- | ≤6” of SAITO are satisfied in the parallel pn layer (3/4), where,
“Qp=Na×Wp” and “Qn=Nd×Wn”,
“Na” and “Wp” respectively represent a carrier concentration and a width of the one first-conductivity-type region included in said each adjacent two regions, and “Nd” and “Wn” respectively represent a carrier concentration and a width of the one second-conductivity-type region included in said each adjacent two regions, “CB1+” corresponds to a CB at a first depth located at a first distance in the first direction away from the standard depth, “CB1-” corresponds to a CB at a second depth located at a second distance in the second direction away from the standard depth, and the first and second distances are the same distance.
With respect to claim 5, the standard condition of SAITO defines amounts of the first-conductivity-type charge (QN) and the second-conductivity-type charge (QP) in each adjacent two regions that obtain a greatest breakdown voltage.
With respect to claim 6, an impurity concentration of the plurality of first-conductivity-type regions (3) of SAITO is constant in the depth direction.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANH D MAI whose telephone number is (571)272-1710 (Anh.Mai2@uspto.gov). The examiner can normally be reached 10:00-4:00PM.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Sue A Purvis can be reached at 571-272-1236. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/ANH D MAI/Primary Examiner, Art Unit 2893
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