A semiconductor device, comprising: a first fin disposed on a substrate, the first fin comprising first, second, third and fourth materials (108; 110; 112; 114), wherein: the first material is disposed between the second material and the substrate, the second material is disposed between the third material and the first material, the third material is disposed between the fourth material and the second material, the first and third materials are formed from a first type of extrinsic semiconductor, and the second and fourth materials are formed from a second type of extrinsic semiconductor, the second type different from the first type; a second fin disposed on the substrate, laterally separated from the first fin, wherein the second fin has a material that is materially contiguous with at least one of the first, second, third or fourth materials; and a first conductive contact disposed on the fourth material, characterised in that: the first fin has a first portion and a second portion; the first, second, third and fourth materials of the first fin are included in the first portion; the second portion includes first and second materials (220; 222); the first material of the second portion is materially contiguous with the first material of the first portion; the second material of the second portion is materially contiguous with the second material of the first portion; and the semiconductor device further comprises a second conductive contact disposed on the second material of the second portion and a third conductive contact disposed on the second fin. a first fin disposed on a substrate, the first fin comprising first, second, third and fourth materials (108; 110; 112; 114), wherein: the first material is disposed between the second material and the substrate, the second material is disposed between the third material and the first material, the third material is disposed between the fourth material and the second material, the first and third materials are formed from a first type of extrinsic semiconductor, and the second and fourth materials are formed from a second type of extrinsic semiconductor, the second type different from the first type; the first material is disposed between the second material and the substrate, the second material is disposed between the third material and the first material, the third material is disposed between the fourth material and the second material, the first and third materials are formed from a first type of extrinsic semiconductor, and the second and fourth materials are formed from a second type of extrinsic semiconductor, the second type different from the first type; a second fin disposed on the substrate, laterally separated from the first fin, wherein the second fin has a material that is materially contiguous with at least one of the first, second, third or fourth materials; and a first conductive contact disposed on the fourth material, characterised in that: the first fin has a first portion and a second portion; the first, second, third and fourth materials of the first fin are included in the first portion; the second portion includes first and second materials (220; 222); the first material of the second portion is materially contiguous with the first material of the first portion; the second material of the second portion is materially contiguous with the second material of the first portion; and the semiconductor device further comprises a second conductive contact disposed on the second material of the second portion and a third conductive contact disposed on the second fin. the first fin has a first portion and a second portion; the first, second, third and fourth materials of the first fin are included in the first portion; the second portion includes first and second materials (220; 222); the first material of the second portion is materially contiguous with the first material of the first portion; the second material of the second portion is materially contiguous with the second material of the first portion; and the semiconductor device further comprises a second conductive contact disposed on the second material of the second portion and a third conductive contact disposed on the second fin.