An alternative In0.3Ga0.7As/In0.29Al0.71As heterostructure based on GaAs is proposed, which provides a large conduction-band discontinuity for a better carrier confinement, resulting in a high-carrier density, This unstrained high-In channel achieved a better device performance, as compared with the conventional pseudomorphic channel, which is always limited by the critical thickness. This unstrained channel is also proven to be more stable after a long-term biased-stress.