Patent ID: 6228693
Filing Date: 2001-05-08
Classification: H01L

Abstract:
A method of crystallizing amorphous semiconductor material overlying a glass substrate to provide for the formation of thin film transistors having increased electron mobility, the method comprising the steps of:a) in an active area of the amorphous semiconductor material where a thin film transistor is formed, depositing a nucleus of transition metal on a selected area of the semiconductor material;b) inducing the crystallization of the amorphous semiconductor material in a crystallized region surrounding the nucleus of transition metal deposited in step a) by means of a single rapid thermal annealing step consisting of:ramping up the temperature to an annealing temperature in the range between 600 and 800 degrees C. and maintaining said annealing temperature for a duration in the range between 1 second and 15 minutes, the induced crystallization proceeding outwardly from said nucleus of transition metal along a lateral growth front that expands to cover an area at least ten times the size of the selected area of the nucleus, whereby said crystallized region is formed in the active area where a thin film transistor is formed; andc) cooling the semiconductor material following said duration of said single rapid thermal annealing step of step b), whereby a continuous region of crystallized semiconductor material having high electron mobility is formed.