Patent ID: 6127692
Filing Date: 2000-10-03
Classification: H01L,Y02E

Abstract:
A photoelectric conversion apparatus comprising:a light absorption layer made of non-monocrystalline material having an energy bandgap Eg1 greater than 1.2 eV;an avalanche multiplication layer comprising a plurality of stepback layers, adjacent stepback layers being interconnected via a heterojunction, each stepback layer made of non-monocrystalline material having an energy bandgap gradually broadening from a minimum energy bandgap Eg2 to a maximum energy bandgap Eg3 in a direction from a light receiving surface side of said avalanche multiplication layer toward an opposing surface side of said avalanche multiplication layer, wherein said light absorption layer is disposed adjacent to said light receiving surface side of said avalanche multiplication layer, wherein said light absorption layer is of sufficient thickness to generate photocarriers by absorbing all incident visible light so that no photocarriers are generated by said avalanche multiplication layer, and wherein a high-concentration impurity layer is provided between two adjacent layers of said plurality of stepback layers;voltage application means for applying to said avalanche multiplication layer a voltage sufficient to cause carrier drift but not sufficient to cause carrier generation by ionization in each said stepback layer; andstorage means being electrically connected to said avalanche multiplication layer for storing carriers generated by avalanche multiplication,wherein the energy difference between the minimum and maximum energy bandgaps is sufficient to cause carrier generation by ionization at an interface between two adjacent layers of said plurality of stepback layers.