A method for manufacturing a semiconductor device, the method comprising: - providing a dielectric isolation layer with an opening on a semiconductor substrate; the opening being confined by a first and a second sidewall surface; the dielectric isolation layer having a top surface; - providing by epitaxial growth in the opening on the semiconductor substrate a fin structure, the fin structure comprising a semiconductor material and protruding above the top surface from the dielectric isolation layer; the fin structure comprising a first and a second opposite exposed sidewall surface being aligned with the first and a second sidewall surface respectively and an exposed top surface; - providing by epitaxial growth on the dielectric isolation layer a first vertical channel layer along and in contact with the first exposed sidewall surface of the fin structure; the first vertical channel layer comprising a first channel material being different from the fin material of the fin structure; the first vertical channel layer having a top surface; - providing by epitaxial growth on the dielectric isolation layer a second vertical channel layer along and in contact with the second exposed sidewall surface of the fin structure; the second vertical channel layer comprising a second channel material being different from the fin material and the second channel material being different from the first channel material of the first vertical channel layer; the second channel layer having a top surface; - providing a dielectric layer on the exposed dielectric isolation layer adjacent and in contact with the first vertical channel layer and the second vertical channel layer, the dielectric layer having a top surface which is substantially aligned with the top surface of the first vertical channel layer and of the second vertical channel layer; - thereafter removing at least a top portion of the fin structure thereby creating a trench, the trench having a bottom surface being lower than the top surface of the dielectric isolation layer; - thereafter providing in the trench a dielectric filling material; - removing top portion of the dielectric layer and the dielectric filling material such that the top surface of the dielectric layer is substantially planarized with the top surface of the dielectric filling material and thereby making the first and the second vertical channel layer freestanding. - providing a dielectric isolation layer with an opening on a semiconductor substrate; the opening being confined by a first and a second sidewall surface; the dielectric isolation layer having a top surface; - providing by epitaxial growth in the opening on the semiconductor substrate a fin structure, the fin structure comprising a semiconductor material and protruding above the top surface from the dielectric isolation layer; the fin structure comprising a first and a second opposite exposed sidewall surface being aligned with the first and a second sidewall surface respectively and an exposed top surface; - providing by epitaxial growth on the dielectric isolation layer a first vertical channel layer along and in contact with the first exposed sidewall surface of the fin structure; the first vertical channel layer comprising a first channel material being different from the fin material of the fin structure; the first vertical channel layer having a top surface; - providing by epitaxial growth on the dielectric isolation layer a second vertical channel layer along and in contact with the second exposed sidewall surface of the fin structure; the second vertical channel layer comprising a second channel material being different from the fin material and the second channel material being different from the first channel material of the first vertical channel layer; the second channel layer having a top surface; - providing a dielectric layer on the exposed dielectric isolation layer adjacent and in contact with the first vertical channel layer and the second vertical channel layer, the dielectric layer having a top surface which is substantially aligned with the top surface of the first vertical channel layer and of the second vertical channel layer; - thereafter removing at least a top portion of the fin structure thereby creating a trench, the trench having a bottom surface being lower than the top surface of the dielectric isolation layer; - thereafter providing in the trench a dielectric filling material; - removing top portion of the dielectric layer and the dielectric filling material such that the top surface of the dielectric layer is substantially planarized with the top surface of the dielectric filling material and thereby making the first and the second vertical channel layer freestanding.