Auto increment nvarcahr id

Dear sir Goodmorning. I have two table, one is TBL_EMP and second is TBL_DEPARTMENT TBL_EMP EMPID, DEPTID, EMPNAME, DOJ, DOB ..... TBL_DEPARTMENT DEPTID, DEPTNAME,
FOR EXAMPLE DEPTNAME are executive, Manager, CEO, I have require empID ex1001, ma1002, CE0003 and so on.............