| 摘要 |
PURPOSE:To obtain a high speed semiconductor laser element capable of performing direct modulation exceeding 10GHz of threshold frequency by a method wherein the barrier layer of the quantum well active layer of the quantum well type laser is doped with high concentration P-type impurities. CONSTITUTION:At a semiconductor laser device having a multiple quantum well active layer formed by piling up alternately a well layer 3 of thickness thinner than de Broglie wavelength of electrons and a barrier layer 4 having forbidden bandwidth larger than that of the well layer 3, the type of conduction of the barrier layer 4 is made to be a P-type. For example, an N-type Ga1-xAlxAs clad layer 2 is grown according to the organic metal vapor growth method on an N-type GaAs substrate 1, and a multiple quantum well construction is grown thereon. The multiple quantum well layer is formed by growing alternately an undoped Ga1-yAlyAs well layer (y=0-0.2, thickness is 3-10nm) 3 and a P-type Ga1-zAlzAs barrier layer (z>y, thickness is 3-20nm) 4 to the 2-10 layers. Then a P-type Ga1-xAlxAs layer 5 and a P-type GaAs layer 6 are grown, a P-side electrode Cr-Au 7 and an N-side electrode AuGeNi-Au 8 are evaporated, and the unit is cut off to obtain a laser element. |
