摘要:
La présente invention concerne un procédé de formation d'une couche de silicium épitaxiée formée de cristallites de taille supérieure ou égale à 20 µm, comprenant au moins les étapes consistant à : (1) disposer d'une couche de silicium cristallisé dont la surface, inhomogène en termes de taille de cristallites, est formée de gros cristallites de taille supérieure ou égale à 20 µm, et de petits cristallites de taille inférieure; (2) constituer, à la surface de ladite couche de silicium inhomogène, une couche d'au moins un matériau non nucléant pour le silicium et dont l'épaisseur est ajustée pour recouvrir l'intégralité de la surface externe desdits petits cristallites tout en laissant accessible tout ou partie de la surface externe desdits gros cristallites; et (3) réaliser la croissance épitaxiale d'une couche de silicium à la surface de l'ensemble obtenu à l'issue de l'étape (2), dans des conditions propices à la formation de ladite couche épitaxiée attendue.
摘要:
The present invention proposes variations of the laser separation method allowing separating homoepitaxial films from the substrates made from the same crystalline material as the epitaxial film. This new method of laser separation is based on using the selective doping of the substrate and epitaxial film with fine donor and acceptor impurities. In selective doping,, concentration of free carries in the epitaxial film and substrate may essentially differ and this can lead to strong difference between the light absorption factors in the infrared region near the residual beams region where free carriers and phonon-plasmon interaction of the optical phonons with free carriers make an essential contribution to infrared absorption of the optical phonons. With the appropriate selection of the doping levels and frequency of infrared laser radiation it is possible to achieve that laser radiation is absorbed in general in the region of strong doping near the interface substrate- homoepitaxial film. When scanning the interface substrate- homoepitaxial film with the focused laser beam of sufficient power, thermal decomposition of the semiconductor crystal takes place with subsequent separation of the homoepitaxial film. The advantage of the proposed variations of the method for laser separation of epitaxial films in comparison with the known ones is in that it allows to separate homoepitaxial films from the substrates, i.e., homoepitaxial films having the same width of the forbidden gap as the initial semiconductor substrate has. The proposed variations of the method can be used for separation of the epitaxial films. Besides, the proposed method allows using the high-effective and inexpensive infrared gas silicon dioxide CO 2 or silicon oxide CO lasers for separation of the epitaxial films.
摘要:
Objects are to provide a semiconductor device for high power application in which a novel semiconductor material having high productivity is used and to provide a semiconductor device having a novel structure in which a novel semiconductor material is used. The present invention is a vertical transistor and a vertical diode each of which has a stacked body of an oxide semiconductor in which a first oxide semiconductor film having crystallinity and a second oxide semiconductor film having crystallinity are stacked. An impurity serving as an electron donor (donor) which is contained in the stacked body of an oxide semiconductor is removed in a step of crystal growth; therefore, the stacked body of an oxide semiconductor is highly purified and is an intrinsic semiconductor or a substantially intrinsic semiconductor whose carrier density is low. The stacked body of an oxide semiconductor has a wider band gap than a silicon semiconductor.
摘要:
The present invention relates to a diamond electronic device comprising a functional interface between two solid materials, wherein the interface is formed by a planar first surface of a first layer of single crystal diamond and a second layer formed on the first surface of the first diamond layer, the second layer being solid, non-metallic and selected from diamond, a polar material and a dielectric material, and wherein the planar first surface of the first layer of single crystal diamond has an Rq of less than 10 nm and has at least one of the following characteristics: (a) the first surface is an etched surface; (b) a density of dislocations in the first diamond layer breaking the first surface is less than 400 cm -2 measured over an area greater than 0.014 cm 2 ; (c) a density of dislocations in the second layer breaking a notional or real surface lying within the second layer parallel to the interface and within 50 µm of the interface is less than 400 cm -2 measured over an area greater than 0.014 cm 2 ; and (d) the first surface has an R q less than 1 nm.
摘要:
Self-aligned fabrication of silicon carbide semiconductor devices is a desirable technique enabling reduction in the number of photolithographic steps, simplified alignment of different device regions, and reduced spacing between the device regions. This invention provides a method of fabricating silicon carbide (SiC) devices utilizing low temperature selective epitaxial growth which allows avoiding degradation of many masking materials attractive for selective epitaxial growth. Another aspect of this invention is a combination of the low temperature selective epitaxial growth of SiC and self-aligned processes.