Wafers including a diamond layer and a semiconductor layer having III-Nitride compounds and methods for fabricating the wafers are provided. A nucleation layer, at least one semiconductor layer having III-Nitride compound and a protection layer are formed on a silicon substrate. Then, a silicon carrier wafer is glass bonded to the protection layer. Subsequently the silicon substrate, nucleation layer and a portion of the semiconductor layer are removed. Then, an intermediate layer, a seed layer and a diamond layer are sequentially deposited on the III-Nitride layer. Next, a substrate wafer that includes a glass substrate (or a silicon substrate covered by a protection layer) is glass bonded to the diamond layer. Then, the silicon carrier wafer and the protection layer are removed.

This diamond composite includes a first base substrate which has an oxide layer of element M and contains the element M in the composition and a second base substrate which is bonded to the oxide layer and is composed of diamond, in which the M is one or more selected from a metal element with which an oxide can be formed, Si, Ge, As, Se, Sb, Te, and Bi, and the second base substrate is bonded to the oxide layer of the first base substrate by M-O—C bonding of at least some C atoms on the surface of the diamond constituting the second base substrate.

Apparatuses and methods are provided for manufacturing diamond electronic devices. The method includes at least one of the following acts: positioning a substrate in a plasma enhanced chemical vapor deposition (PECVD) reactor; controlling temperature of the substrate by manipulating microwave power, chamber pressure, and gas flow rates of the PECVD reactor; and growing phosphorus doped diamond layer on the substrate using a pulsed deposition comprising a growth cycle and a cooling cycle.

Peak concentration of the carrier accumulation layer is equal to or higher than 1.0E16/cm.sup.3. A bottom part of the trench is positioned inside the n-type carrier accumulation layer. When a concentration ratio is a result of division of a concentration of the carrier accumulation layer by a concentration of the drift layer at a depth of the bottom part of the trench, the depth of the bottom part of the trench is a position at which the concentration ratio is larger than one and equal to or smaller than 10.

A semiconductor device of the present invention includes a semiconductor layer of a first conductivity type having a cell portion and an outer peripheral portion disposed around the cell portion, and a surface insulating film disposed in a manner extending across the cell portion and the outer peripheral portion, and in the cell portion, formed to be thinner than a part in the outer peripheral portion.

The plurality of first control electrodes extend in a first direction in a planar view, the plurality of second control electrodes extend in a second direction in a planar view. A sum of lengths in the first direction of boundaries between the second semiconductor layer and the plurality of third semiconductor layers on a surface of the semiconductor substrate which faces the plurality of first control electrodes is set as a first gate total width. A sum of lengths in the second direction of boundaries between the fourth semiconductor layer and the plurality of fifth semiconductor layers on a surface of the semiconductor substrate which faces the plurality of second control electrodes is set as a second gate total width. A gate width ratio obtained by dividing the second gate total width by the first gate total width is equal to or higher than 1.0.

A semiconductor device includes an N-type drift layer provided between a first main surface and a second main surface of the semiconductor substrate and an N-type buffer layer provided between the N-type drift layer and the first main surface and having a higher impurity peak concentration than the N-type drift layer. The N-type buffer layer has a structure that a first buffer layer, a second buffer layer, a third buffer layer, and a fourth buffer layer are disposed in this order from a side of the first main surface. When a distance from an impurity peak position of the first buffer layer to an impurity peak position of the second buffer layer is L12 and a distance from an impurity peak position of the second buffer layer to an impurity peak position of the third buffer layer is L23, a relationship of L23/L12≥3.5 is satisfied.

A semiconductor device includes a monocrystalline substrate of a material which does not have a liquid phase at atmospheric pressure, and an identification mark disposed on or in the substrate comprising an amorphous region of the material or a region of the material deviated from stoichiometry.

A semiconductor device of the present invention includes a semiconductor layer of a first conductivity type having a cell portion and an outer peripheral portion disposed around the cell portion, formed with a gate trench at a surface side of the cell portion, and a gate electrode buried in the gate trench via a gate insulating film, forming a channel at a portion lateral to the gate trench at ON-time, the outer peripheral portion has a semiconductor surface disposed at a depth position equal to or deeper than a depth of the gate trench, and the semiconductor device further includes a voltage resistant structure having a semiconductor region of a second conductivity type formed in the semiconductor surface of the outer peripheral portion.

A trenched MOS gate controlled rectifier has an asymmetric trench structure between the active area of active trenches and the termination area of termination trenches. The asymmetric trench structure has a gate electrode on one side of the trench to turn on and off the channel of the MOS structure effectively and a field plate structure on the other side with field dielectric sufficiently thick in order to sustain the high electric field during the reverse bias condition.