Strained Layer Superlattice Structures Research Articles

Preparation of III-V compound semiconductors by metal organic chemical vapor deposition

The technique of decomposing metal organics and/or hydrides on a hot substrate has been used to prepare device quality GaAs, GaP, and Ga(AsP). These compounds can be deposited in either single crystal or polycrystalline form on a variety of substrates. Single crystal epitaxial layers have been grown under well-defined conditions with impurity concentrations of approx. 10/sup 14/ cm/sup -3/ for GaAs. The addition of impurity metal organics or hydrides allows one to prepare n-type, p-type, and semiinsulating layers. Rectifying diodes with reverse leakage currents of < 10 ..mu..A at 120 V have been prepared in GaP using Zn as a dopant. Strained layer superlattice structures which consist of very thin layers (< 300 A) of alternating compositions have been grown using metal organic chemical vapor deposition. Such structures in the Ga(AsP) + GaP system minimize dislocation formation between these lattice mismatched materials and have a unique band structure. The measured band gap for a 60-A GaAs/sub 0/ /sub 4/P/sub 0/ /sub 6//GaP superlattice at 77 K is 2.03 eV.