Abstract: A semiconductor device includes: a substrate; a buffer layer including GaN formed on the substrate, wherein: surfaces of the buffer layer are c facets of Ga atoms; a channel layer including GaN or InGaN formed on the buffer layer, wherein: surfaces of the channel layer are c facets of Ga or In atoms; an electron donor layer including AlGaN formed on the channel layer, wherein: surfaces of the electron donor layer are c facets of Al or Ga atoms; a source electrode and a drain electrode formed on the electron donor layer; a cap layer including GaN or InGaAlN formed between the source electrode and the drain electrode, wherein: surfaces of the cap layer are c facets of Ga or In atoms and at least a portion of the cap layer is in contact with the electron donor layer; and a gate electrode formed at least a portion of which is in contact with the cap layer.

Abstract: A first resist film for EB exposure, a buffer film, and a second resist film for i-line exposure are applied sequentially onto a substrate. Thereafter, the second resist film and the buffer film are subjected to patterning for forming a first opening. Then, dry etching is performed with respect to the first resist film masked with the second resist film to transfer the pattern of the second resist film to the first resist film and thereby form a second opening in the first resist film. Subsequently, a third resist film of chemically amplified type is applied to the entire surface of the first resist film to form a mixing layer in conjunction with the first resist film. As a result, the wall faces of the second opening are covered with the mixing layer and the width of the second opening is thereby reduced.

Abstract: A heterojunction epitaxial layer, including a first semiconductor layer containing Al and having a thickness of 50 nm or less and a second semiconductor layer different in composition from the first semiconductor layer, is formed on a substrate composed of semi-insulating GaAs. A gate electrode is formed on a specified region of the top surface of the heterojunction epitaxial layer. The source/drain formation regions of the heterojunction epitaxial layer are provided with respective high-concentration N-type impurity diffusion regions, on which respective ohmic electrodes are formed.

Abstract: In fabricating an MFIC by mounting a semiconductor chip on a substrate having a microstrip line by MBB bonding, a benzocyclobutene (BCB) film is used as a dielectric film of the microstrip line. By providing a means for preventing the deformation, peeling, and cracking of the BCB film during the fabrication process, the thickness of the dielectric film is held substantially equal even after flip-chip mounting, which reduces impedance fluctuations.

Abstract: On a semi-insulating substrate is formed a conductive layer and an undoped layer. On specified regions of the conductive layer are formed ohmic electrodes, each serving as a source electrode or a drain electrode, via a pair of square contact regions. The circumferential edges of the contact regions are undercut beneath the ohmic electrodes. Between the pair of contact regions on the conductive layer is formed a gate electrode by self alignment using the ohmic electrodes as a mask. The gate electrode has extended in the direction of gate width and the extended portion serves as a withdrawn portion of the gate electrode. Upper electrodes are formed by self alignment in the same process in which the gate electrode is formed.

Abstract: A fine structure T-shaped electrode is fabricated using a phase shift method. A photoresist layer is formed on a semiconductor substrate and the photoresist layer is exposed to an exposure light having a first wavelength through a photomask which has a desired pattern of a base shifting layer whereby the phase of the exposure light is shifted by 180 degrees. The photoresist layer is then exposed to another exposure light having a second wavelength that is different from the first wavelength through the photomask. The photoresist is developed to form a T-shaped resist cavity and a metal layer is deposited over the resist layer formed on the semiconductor substrate. All the metal layer is removed except for the areas covering the T-shaped photoresist pattern. The T-shaped electrode is also formed by disposing a photoresist layer on a semiconductor substrate.