Light detection device including a semiconductor light detection element, a mounting substrate, and quenching circuits wherein the first electrodes of the light detection element corresponding to the second electrodes of the mounting substrate are electrically connected through bump electrodes

1. A light detection device comprising:

a semiconductor light detection element including a semiconductor substrate including first and second principal surfaces opposed to each other, a plurality of avalanche photodiodes operating in Geiger mode and formed in the semiconductor substrate, and first electrodes electrically connected to the respective avalanche photodiodes and arranged on the second principal surface side of the semiconductor substrate:

a mounting substrate including a third principal surface opposed to the second principal surface of the semiconductor substrate, and a plurality of second electrodes arranged corresponding to the respective first electrodes on the third principal surface side, the mounting substrate being arranged as opposed to the semiconductor light detection element; and

quenching circuits electrically connected to the respective second electrodes,

wherein the first electrodes and the second electrodes corresponding to the first electrodes are electrically connected through bump electrodes, and

wherein the quenching circuits are not arranged on the semiconductor substrate of the semiconductor light detection element.

2. The light detection device according to claim 1 ,

wherein each of the avalanche photodiodes includes:

the semiconductor substrate of a first conductivity type;

a first semiconductor region of a second conductivity type formed on the first principal surface side of the semiconductor substrate;

a second semiconductor region of the second conductivity type formed in the first semiconductor region and having a higher impurity concentration than the first semiconductor region; and

a third electrode arranged on the first principal surface side of the semiconductor substrate and electrically connected to the second semiconductor region, and

wherein in the semiconductor substrate, a through-hole electrode penetrating from the first principal surface side to the second principal surface side and electrically connecting the corresponding third electrode and first electrode is formed for each avalanche photodiode.

3. The light detection device according to claim 1 ,

wherein each of the avalanche photodiodes includes:

the semiconductor substrate of a first conductivity type;

a first semiconductor region of a second conductivity type formed on the second principal surface side of the semiconductor substrate; and

a second semiconductor region of the first conductivity type forming a PN junction with the first semiconductor region and having a higher impurity concentration than the semiconductor substrate, and

wherein the first semiconductor region and the first electrode are electrically connected.

4. The light detection device according to claim 1 ,

wherein the mounting substrate further includes a common electrode to which the quenching circuits are connected in parallel.

5. The light detection device according to claim 1 ,

wherein the quenching circuits are passive quenching circuits or active quenching circuits.