QUANTUM-WELL HALL DEVICES IN SI-DELTA-DOPED AL0.25GA0.75AS GAAS AND PSEUDOMORPHIC AL0.25GA0.75AS/IN0.25GA0.75AS/GAAS HETEROSTRUCTURES GROWNBY LP-MOCVD - PERFORMANCE COMPARISONS/

Characterized herein are quantum-well Hall devices in Si-delta-doped A l0.25Ga0.75As/GaAs and pseudomorphic Al0.25Ga0.75As/In0.25Ga0.75As/GaA s heterostructures, grown by low-pressure metal organic chemical vapor deposition method. The Si-delta-doping technique has been applied to quantum-well Hall devices for the first time. As a result high electro n mobilities of 8100 cm(2)/V . s with a sheet electron density of 1.5 x 10(12) cm(-2) in Al0.25Ga0.75As/In0.25Ga0.75As/GaAs structure and of 6000 cm(2)/V . s with the sheet electron density of 1.2 x 10(12) cm(- 2) in Al0.25Ga0.75As/GaAs structure have been achieved at room tempera ture, respectively. From Hall devices in Al0.25Ga0.75As/In0.25Ga0.75As structure, the product sensitivity of 420 V/AT with temperature coeff icient of -0.015 %/K has been obtained. This temperature characteristi cs is one of the best result reported. Additionally, a high signal-to- noise ratio corresponding to the minimum detectable magnetic field of 45 nT at 1 kHz and 75 nT at 100 Hz has been attained. These resolution s are among the best reported results.