bigdatetime and bigtime provide microsecond precision.
Two new datatypes, bigdatetime and bigtime, provide a timestamp with microsecond precision that contains the year, month, day, hour, minute, second, and fraction of a second to six decimal places. A bigdatetime value requires 8 bytes of storage. A bigtime value contains the time of day, containing hour, minute, second, and fraction of a second. The fraction is stored to six decimal places. A bigtime value requires 8 bytes of storage.
See the Adaptive Server Transact-SQL Users Guide, the Reference Manual: Building Blocks, and Java in Adaptive Server Enterprise.