Fabrication of Uniaxially/Biaxially Tensile-Strained Ge by Strain Redistribution Method for Photoelectric Detection Application

Tensile strain is a widely discussed method to improve electron mobility and luminescence of Ge and has been applied in infrared photodetectors. By combining thin film crimping technology with microelectronic processing technology, uniaxial or biaxial tensile strain is achieved in a suspended Ge micro-bridge structure. The strain state can be manipulated by adjusting the sizes of the patterns, and a uniaxial tensile strain of 3.46% and biaxial tensile strain of 0.31% have been demonstrated in this work. The three-dimensional finite element analysis proves that the tensile strain originates from the strain redistribution between the W film and the Ge micro-bridge structure, and finally, the simulation results agree with the experimental data very well.