Found 3 alternatives for ATSAMD20J14B-AUT by Microchip Technology. Embedded Microcontrollers — 64-TQFP Exposed Pad.
IC MCU 32BIT 32KB FLASH 64TQFP
IC MCU 32BIT ROMLESS 64TQFP
IC MCU 32BIT 1MB FLASH 64TQFP